Remove unnecessary and obsolete configure.ac directives

Also enable silent rules where missing

Change-Id: Ia521886815c862b013f01df4cc18fd8a298aaaa1
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/g2/configure.ac b/g2/configure.ac
index cd6522f..c8af774 100644
--- a/g2/configure.ac
+++ b/g2/configure.ac
@@ -1,13 +1,12 @@
 AC_INIT(g2, 3.0)
 AM_INIT_AUTOMAKE
+AM_SILENT_RULES([yes])
 
 AC_CHECK_LIB([vppinfra], [clib_mem_get_page_size],,
         AC_MSG_ERROR([Please install the vpp-lib package]))
 AC_CHECK_HEADER([vppinfra/clib.h],,
         AC_MSG_ERROR([Please install the vpp-dev package]))
 
-AM_PROG_AS
-AM_PROG_CC_C_O
 PKG_CHECK_MODULES(g2, gtk+-2.0)
 
 AC_OUTPUT([Makefile])