Be sure workspace is initialized

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@1388 65c4cc65-6c06-0410-ace0-fbb531ad65f3

pbx.c

@@ -993,6 +993,7 @@ void pbx_substitute_variables_helper(struct ast_channel *c,const char *cp1,char
 			}
 			
 			/* Retrieve variable value */
+			strcpy(workspace, "");
 			pbx_substitute_variables_temp(c,vars,&cp4, workspace, sizeof(workspace));
 			if (cp4) {
 				length = strlen(cp4);