restore support for --defaults-file=<(...)

if my_realpath() fails, don't return the error code, get_defaults_options()
returns a number of options consumed, not 0=ok/1=error.

instead, ignore the error from my_realpath. If it fails it internally
falls back to my_load_path, which restores 10.4- behavior

mysql-test/main/mysqld--defaults-file.result

@@ -2,11 +2,11 @@ Could not open required defaults file: /path/with/no/extension
 Fatal error in defaults handling. Program aborted
 Could not open required defaults file: /path/with.ext
 Fatal error in defaults handling. Program aborted
-Could not open required defaults file: relative/path/with.ext
+Could not open required defaults file: MYSQL_TEST_DIR/relative/path/with.ext
 Fatal error in defaults handling. Program aborted
-Could not open required defaults file: relative/path/without/extension
+Could not open required defaults file: MYSQL_TEST_DIR/relative/path/without/extension
 Fatal error in defaults handling. Program aborted
-Could not open required defaults file: with.ext
+Could not open required defaults file: MYSQL_TEST_DIR/with.ext
 Fatal error in defaults handling. Program aborted
-Could not open required defaults file: no_extension
+Could not open required defaults file: MYSQL_TEST_DIR/no_extension
 Fatal error in defaults handling. Program aborted

mysql-test/main/mysqld--defaults-file.test

@@ -7,21 +7,27 @@ source include/not_windows.inc;
 
 # All these tests refer to configuration files that do not exist
 
+--replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=/path/with/no/extension --print-defaults 2>&1;
 
+--replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=/path/with.ext --print-defaults 2>&1;
 
+--replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=relative/path/with.ext --print-defaults 2>&1;
 
+--replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=relative/path/without/extension --print-defaults 2>&1;
 
+--replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=with.ext --print-defaults 2>&1;
 
+--replace_result $MYSQL_TEST_DIR MYSQL_TEST_DIR
 --error 1
 exec $MYSQLD --defaults-file=no_extension --print-defaults 2>&1;
 

mysys/my_default.c

@@ -322,17 +322,13 @@ int get_defaults_options(char **argv)
 
   if (my_defaults_extra_file && my_defaults_extra_file != extra_file_buffer)
   {
-    int error= my_realpath(extra_file_buffer, my_defaults_extra_file, MYF(0));
-    if (error)
-      return error;
+    my_realpath(extra_file_buffer, my_defaults_extra_file, MYF(0));
     my_defaults_extra_file= extra_file_buffer;
   }
 
   if (my_defaults_file && my_defaults_file != file_buffer)
   {
-    int error= my_realpath(file_buffer, my_defaults_file, MYF(0));
-    if (error)
-      return error;
+    my_realpath(file_buffer, my_defaults_file, MYF(0));
     my_defaults_file= file_buffer;
   }