VMM/config: Updated Dovecot version check.
Renamed function check_version_format() -> check_dovecot_version().
Now this function checks also if misc.dovecot_version >= MIN_DOVECOT_VERSION.
.. |curr_vers_rel_date| replace:: The most current version of vmm is 0.6.2,
released on 01 February 2014.
.. |rel_hist| replace:: Older releases are listed in the :doc:`release_history`.