contribs: hide debug output by default

It is useless to most people and folks who understand it, will edit config.mak anyway
Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

extras/contrib/bootstrap

@@ -33,7 +33,7 @@ fi
 LANG=C
 export LANG
 set -e
-set -x
+set +x
 
 BUILD=`gcc -dumpmachine`
 if test "$#" -ge "1"; then