Disable build of Python bindings, which requires the sipconfig module.

Signed-off-by: Simon Dawson <spdawson@gmail.com>
Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>

diff -purN libserial-0.6.0rc2.orig/Makefile.am libserial-0.6.0rc2/Makefile.am
--- libserial-0.6.0rc2.orig/Makefile.am	2014-06-05 18:37:25.000000000 +0200
+++ libserial-0.6.0rc2/Makefile.am	2015-07-30 20:59:28.828429011 +0200
@@ -1,4 +1,4 @@
-SUBDIRS=src doc examples sip
+SUBDIRS=src doc examples
 ACLOCAL_AMFLAGS=-I m4
 
 EXTRA_DIST = doxygen.conf.in Makefile.dist libserial.spec libserial.pc
diff -purN libserial-0.6.0rc2.orig/Makefile.in libserial-0.6.0rc2/Makefile.in
--- libserial-0.6.0rc2.orig/Makefile.in	2014-06-05 18:40:09.000000000 +0200
+++ libserial-0.6.0rc2/Makefile.in	2015-07-30 21:00:09.215188376 +0200
@@ -348,7 +348,7 @@ target_alias = @target_alias@
 top_build_prefix = @top_build_prefix@
 top_builddir = @top_builddir@
 top_srcdir = @top_srcdir@
-SUBDIRS = src doc examples sip
+SUBDIRS = src doc examples
 ACLOCAL_AMFLAGS = -I m4
 EXTRA_DIST = doxygen.conf.in Makefile.dist libserial.spec libserial.pc
 pkgconfigdir = $(libdir)/pkgconfig