Cassandra RPM has wrong owner for /usr/share directories

Some Cassandra RPM directories are owned by cassandra user against the fedora package guidelines.

Offending lines: https://github.com/apache/cassandra/blob/trunk/redhat/cassandra.spec#L135-L136

"Permissions on files MUST be set properly. Inside of /usr, files should be owned by root:root unless a more specific user or group is needed for security."

• https://fedoraproject.org/wiki/Packaging:Guidelines?rd=Packaging/Guidelines#File_Permissions