Port: Fix bug 1588344 (Memory leak in non-existing defaults file hand…

…ling)

Summary:
Port the following commit from percona server:
percona/percona-server@4344909

Fix bug 1588344 (Memory leak in non-existing defaults file handling)

Ensure that dynamic array args is freed on error exits in
my_load_defaults.

Test Plan:
mtr

main.mysqld--defaults-file in asan build (gcc5)

Reviewers: gunnarku

Reviewed By: gunnarku

Subscribers: webscalesql-eng@fb.com

Differential Revision: https://phabricator.intern.facebook.com/D5196926

Tasks: 17217920

Signature: t1:5196926:1496808391:ce92a69cf9ee385d92cec8f25151db5c2595d7bf

mysys_ssl/my_default.cc

@@ -663,6 +663,7 @@ int my_load_defaults(const char *conf_file, const char **groups,
                                      &args_used, handle_default_option,
                                      (void *) &ctx, dirs, false, found_no_defaults)))
   {
+    delete_dynamic(&args);
     free_root(&alloc,MYF(0));
     DBUG_RETURN(error);
   }
@@ -675,6 +676,7 @@ int my_load_defaults(const char *conf_file, const char **groups,
                                      handle_default_option, (void *) &ctx,
                                      dirs, true, found_no_defaults)))
     {
+      delete_dynamic(&args);
       free_root(&alloc, MYF(0));
       DBUG_RETURN(error);
     }
@@ -685,7 +687,10 @@ int my_load_defaults(const char *conf_file, const char **groups,
   */
   if (!(ptr=(char*) alloc_root(&alloc,sizeof(alloc)+
 			       (args.elements + *argc + 1 + args_sep) *sizeof(char*))))
+  {
+    delete_dynamic(&args);
     goto err;
+  }
   res= (char**) (ptr+sizeof(alloc));
 
   /* copy name + found arguments + command line arguments to new array */