configure.ac: disable -Werror

Disable the mandatory flag -Werror in configure.ac.

Signed-off-by: Karoly Kasza <kaszak@gmail.com>

--- open-vm-tools/configure.ac	2015-06-17 10:02:00.000000000 +0200
+++ open-vm-tools/configure.ac	2015-06-17 10:02:00.000000000 +0200
@@ -935,7 +935,7 @@
 
 ### General flags / actions
 CFLAGS="$CFLAGS -Wall"
-CFLAGS="$CFLAGS -Werror"
+# CFLAGS="$CFLAGS -Werror"
 
 # -Wno-unknown-pragmas is due to gcc not understanding '#pragma ident'
 # in Xlib.h on OpenSolaris.