Fixed: Avoid DPKG error while switching from MySQL to MariaDB and vice-versa

    [feedquote='i-MSCP Github (nuxwin)','https://github.com/i-MSCP/imscp/commit/d938745fc6760913c5f74588445a2e683a1e3fd1']

    Code
    1. Fixed: Avoid DPKG error while switching from MySQL to MariaDB and vice-versa
    2. Small fixes

    [/feedquote]