Only try to clean out h323/ if the h323/Makefile exists.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@87650 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/Makefile

@@ -67,7 +67,7 @@ ifneq ($(wildcard h323/Makefile.ast),)
   include h323/Makefile.ast
 H323LDFLAGS+=-Wl,--version-script=h323/noexport.map
 clean::
-	$(MAKE) -C h323 clean
+	if [ -f h323/Makefile ]; then $(MAKE) -C h323 clean; fi
 else
 h323/libchanh323.a h323/Makefile.ast:
 	$(CMD_PREFIX) $(MAKE) -C h323