MDEV-14265 - RPMLint warning: shared-lib-calls-exit

find_type_or_exit() client helper did exit(1) on error, exit(1) moved to
clients.

mysql_read_default_options() did exit(1) on error, error is passed through and
handled now.

my_str_malloc_default() did exit(1) on error, replaced my_str_ allocator
functions with normal my_malloc()/my_realloc()/my_free().

sql_connect.cc did many exit(1) on hash initialisation failure. Removed error
check since my_hash_init() never fails.

my_malloc() did exit(1) on error. Replaced with abort().

my_load_defaults() did exit(1) on error, replaced with return 2.

my_load_defaults() still does exit(0) when invoked with --print-defaults.

client/mysqlshow.c

@@ -328,8 +328,12 @@ get_one_option(int optid, const struct my_option *opt __attribute__((unused)),
 #endif
     break;
   case OPT_MYSQL_PROTOCOL:
-    opt_protocol= find_type_or_exit(argument, &sql_protocol_typelib,
-                                    opt->name);
+    if ((opt_protocol= find_type_with_warning(argument, &sql_protocol_typelib,
+                                              opt->name)) <= 0)
+    {
+      sf_leaking_memory= 1; /* no memory leak reports here */
+      exit(1);
+    }
     break;
   case '#':
     DBUG_PUSH(argument ? argument : "d:t:o");