mariadb-galera 5.5.36 build contains shared/common/etc rpm MariaDB-galera packages. This is wrong, only MariaDB-galera-server should be built. Other packages are built now because of the merge error.
Somthing to think of — all non-server packages used to be exactly identical in galera and non-galera tree. But now there are galera-specific test files, perhaps we need MariaDB-galera-test package too?
Another thought — perhaps the wrong set of packages to built was not the only merge error in cpack_rpm..cmake