This is the yum transaction error. Using a local yum repo here, but that's not relevant.

[root@localhost /]# yum upgrade
Loaded plugins: langpacks, presto, refresh-packagekit
Resolving Dependencies
--> Running transaction check
---> Package MariaDB-Galera-server.i686 0:5.5.33a-1 will be obsoleting
--> Processing Dependency: galera for package: MariaDB-Galera-server-5.5.33a-1.i686
--> Processing Dependency: MariaDB-common for package: MariaDB-Galera-server-5.5.33a-1.i686
---> Package MariaDB-devel.i686 0:5.5.33a-1 will be obsoleting
---> Package MariaDB-server.i686 0:5.5.33a-1 will be obsoleting
---> Package MariaDB-shared.i686 0:5.5.33a-1 will be obsoleting
---> Package mysql-devel.i686 0:5.5.34-1.fc18 will be obsoleted
---> Package mysql-libs.i686 0:5.5.34-1.fc18 will be obsoleted
--> Processing Dependency: real-mysql-libs(x86-32) = 5.5.34-1.fc18 for package: mysql-5.5.34-1.fc18.i686
---> Package mysql-server.i686 0:5.5.34-1.fc18 will be obsoleted
--> Running transaction check
---> Package MariaDB-common.i686 0:5.5.33a-1 will be installed
---> Package galera.i686 0:23.2.7-1.fc18 will be installed
---> Package mysql-libs.i686 0:5.5.34-1.fc18 will be obsoleted
--> Processing Dependency: real-mysql-libs(x86-32) = 5.5.34-1.fc18 for package: mysql-5.5.34-1.fc18.i686
--> Processing Conflict: mysql-5.5.34-1.fc18.i686 conflicts MySQL
--> Processing Conflict: mysql-5.5.34-1.fc18.i686 conflicts MySQL
--> Restarting Dependency Resolution with new changes.
--> Running transaction check
---> Package galera.i686 0:23.2.7-1.fc18 will be installed
--> Processing Dependency: galera for package: MariaDB-Galera-server-5.5.33a-1.i686
--> Processing Dependency: galera for package: MariaDB-Galera-server-5.5.33a-1.i686
---> Package mysql-libs.i686 0:5.5.34-1.fc18 will be obsoleted
--> Processing Dependency: real-mysql-libs(x86-32) = 5.5.34-1.fc18 for package: mysql-5.5.34-1.fc18.i686
--> Finished Dependency Resolution
Error: Package: mysql-5.5.34-1.fc18.i686 (@updates)
Requires: real-mysql-libs(x86-32) = 5.5.34-1.fc18
Removing: mysql-libs-5.5.34-1.fc18.i686 (@updates)
real-mysql-libs(x86-32) = 5.5.34-1.fc18
Obsoleted By: MariaDB-shared-5.5.33a-1.i686 (mariadb-local-test-repo)
Not found
Error: mysql conflicts with MariaDB-server-5.5.33a-1.i686
Error: mysql conflicts with MariaDB-Galera-server-5.5.33a-1.i686
Error: Package: MariaDB-Galera-server-5.5.33a-1.i686 (mariadb-local-test-repo)
Requires: galera
You could try using --skip-broken to work around the problem
You could try running: rpm -Va --nofiles --nodigest