fix --srcdir for modules.conf

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@15526 d0543943-73ff-0310-b7d9-9358b9ac24b2

Makefile.am

@@ -513,7 +513,7 @@ libclean:
 	@for file in `ls ./libs`; do pushd "./libs/"$$file; make clean; rm -f .built; popd; done
 
 modules.conf:
-	if test -f $@; then touch $@; else cp build/modules.conf.in $@ ;fi
+	if test -f $@; then touch $@; else cp $(switch_srcdir)/build/modules.conf.in $@ ;fi
 
 $(OUR_MODULES):
 	@set fnord $$MAKEFLAGS; amf=$$2; \