Ticket #1588: rpm extfs enhancements:

  * Improve support for EPOCH
  * Add support for PREINPROG/POSTINPROG/PREUNPROG/POSTUNPROG
  * Add support for VERIFYSCRIPTPROG
  * Add support for TRIGGERSCRIPTS/TRIGGERSCRIPTPROG

Thanks Arkadiusz Miśkiewicz <arekm@maven.pl> for the original patch.

Signed-off-by: Andrew Borodin <aborodin@vmail.ru>
Merge branch '1588_rpm_enhancement'

* 1588_rpm_enhancement:
  Ticket #1588: rpm extfs enhancements: