This commit removes the hard coded value of open-file-limit (16384)
and allows operators to override it via:
tripleo::profile::pacemaker::database::mysql::open_files_limit
tripleo::profile::pacemaker::database::mysql_bundle::open_files_limit
manually cherry picked from: I4927eb65a2dc1b5a86fc2141c7b2713f36ad49de
Change-Id: Icecdf2f6c806b66266a0c10642b18f47a99d1e65
Resolves: rhbz#1812969