Update S3 engine to maturity Gamma

mysql-test/suite/s3/my.cnf

@@ -2,7 +2,7 @@
 !include include/default_client.cnf
 
 [mysqld.1]
-plugin-maturity = alpha
+plugin-maturity = gamma
 plugin-load-add=@ENV.HA_S3_SO
 s3=ON
 #s3-host-name=s3.amazonaws.com

mysql-test/suite/s3/slave.cnf

 [mysqld.2]
-plugin-maturity = alpha
+plugin-maturity = gamma
 plugin-load-add=@ENV.HA_S3_SO
 s3=ON
 s3-slave-ignore-updates=1

storage/maria/ha_s3.cc

@@ -1110,6 +1110,6 @@ maria_declare_plugin(s3)
   status_variables,             /* status variables */
   system_variables,             /* system variables */
   "1.0",                        /* string version   */
-  MariaDB_PLUGIN_MATURITY_ALPHA /* maturity         */
+  MariaDB_PLUGIN_MATURITY_GAMMA /* maturity         */
 }
 maria_declare_plugin_end;