component/mariadb: version down 10.1.21, because of a serious bug in 10.1.22.

https://jira.mariadb.org/browse/MDEV-12281

component/mariadb/buildout.cfg

@@ -22,8 +22,8 @@ parts =
 
 [mariadb]
 recipe = slapos.recipe.cmmi
-url = http://ftp.osuosl.org/pub/mariadb/mariadb-10.1.22/source/mariadb-10.1.22.tar.gz
-md5sum = 8d11f4e20d3ef0bb1befe173de9213c8
+url = https://downloads.mariadb.com/MariaDB/mariadb-10.1.21/source/mariadb-10.1.21.tar.gz
+md5sum = ff8b96edeeb22425117309a249055310
 patch-options = -p0
 patches =
   ${:_profile_base_location_}/mariadb_10.1.21_create_system_tables__no_test.patch#3c76aa9564a162f13aced7c0a3f783b3