urg: fix 'narrowing conversion' with gcc6

Fixes:
  http://autobuild.buildroot.net/results/d0c/d0cd11163753db69a14c02e941dbda40e5f98bba/

Signed-off-by: Samuel Martin <s.martin49@gmail.com>

--- a/src/cpp/urg/ScipHandler.cpp	2016-09-11 16:11:16.083995214 +0200
+++ b/src/cpp/urg/ScipHandler.cpp	2016-09-11 16:11:24.380832543 +0200
@@ -120,7 +120,7 @@ struct ScipHandler::pImpl
 
       // QT の発行
       int return_code = -1;
-      char qt_expected_response[] = { 0, -1 };
+      char qt_expected_response[] = { 0, (char)-1 };
       // return_code を使いたいため、setLaserOutput() を用いずに QT を送信する
       if (response(return_code, "QT\n", qt_expected_response)) {
         laser_state_ = LaserOff;
@@ -139,7 +139,7 @@ struct ScipHandler::pImpl
 
       } else if (return_code == Scip11Response) {
         // SCIP1.1 プロトコルの場合のみ、SCIP2.0 を送信する
-        char scip20_expected_response[] = { 0, -1 };
+        char scip20_expected_response[] = { 0, (char)-1 };
         if (! response(return_code, "SCIP2.0\n", scip20_expected_response)) {
           error_message_ =
             "SCIP1.1 protocol is not supported. Please update URG firmware, or reconnect after a few seconds because sensor is booting.";
@@ -150,7 +150,7 @@ struct ScipHandler::pImpl
 
       } else if (return_code == 0xE) {
         // TM モードとみなし、TM2 を発行する
-        char tm2_expected_response[] = { 0, -1 };
+        char tm2_expected_response[] = { 0, (char)-1 };
         if (response(return_code, "TM2\n", tm2_expected_response)) {
           laser_state_ = LaserOff;
           return changeBothBaudrate(baudrate);
@@ -202,7 +202,7 @@ struct ScipHandler::pImpl
     snprintf(send_buffer, 10, "SS%06ld\n", baudrate);
     int return_code = -1;
     // !!! 既に設定対象のボーレート、の場合の戻り値を ss_expected... に追加する
-    char ss_expected_response[] = { 0, 0x3, 0x4, 0xf, -1 };
+    char ss_expected_response[] = { 0, 0x3, 0x4, 0xf, (char)-1 };
     if (! response(return_code, send_buffer, ss_expected_response)) {
       error_message_ = "Baudrate change fail.";
       return false;
@@ -216,7 +216,7 @@ struct ScipHandler::pImpl
   {
     // PP の送信とデータの受信
     int return_code = -1;
-    char pp_expected_response[] = { 0, -1 };
+    char pp_expected_response[] = { 0, (char)-1 };
     vector<string> lines;
     if (! response(return_code, "PP\n", pp_expected_response, &lines)) {
       error_message_ = "PP fail.";
@@ -356,7 +356,7 @@ struct ScipHandler::pImpl
 
     if (on) {
       int return_code = -1;
-      char expected_response[] = { 0, -1 };
+      char expected_response[] = { 0, (char)-1 };
       if (! response(return_code, "BM\n", expected_response)) {
         error_message_ = "BM fail.";
         return false;
@@ -369,7 +369,7 @@ struct ScipHandler::pImpl
       if (! mx_capturing_) {
         // 消灯するための QT では、応答を待つべき
         int return_code = -1;
-        char qt_expected_response[] = { 0, -1 };
+        char qt_expected_response[] = { 0, (char)-1 };
         if (! response(return_code, "QT\n", qt_expected_response)) {
           return false;
         }
@@ -777,7 +777,7 @@ bool ScipHandler::loadParameter(RangeSen
 bool ScipHandler::versionLines(vector<string>& lines)
 {
   int return_code = -1;
-  char expected_response[] = { 0, -1 };
+  char expected_response[] = { 0, (char)-1 };
   if (! pimpl->response(return_code, "VV\n", expected_response, &lines)) {
     return false;
   }
@@ -792,7 +792,7 @@ bool ScipHandler::setRawTimestampMode(bo
 
   // TM0 or TM2 の送信
   int return_code = -1;
-  char expected_response[] = { 0, -1 };
+  char expected_response[] = { 0, (char)-1 };
   if (! pimpl->response(return_code, send_command, expected_response)) {
     pimpl->error_message_ = (on) ? "TM0 fail." : "TM2 fail.";
     return false;
@@ -809,7 +809,7 @@ bool ScipHandler::rawTimestamp(int* time
 {
   // TM1 の値を返す
   int return_code = -1;
-  char expected_response[] = { 0, -1 };
+  char expected_response[] = { 0, (char)-1 };
   vector<string> lines;
   if (! pimpl->response(return_code, "TM1\n", expected_response, &lines)) {
     pimpl->error_message_ = "TM1 fail.";