dmeventd: avoid bail out preventing repair in raid plugin

dmeventd: avoid bail out preventing repair in raid plugin

Problem:
even though dead raid component devices are detected, the
raid plugin is bailing out thus preventing a repair attempt.

Rational:
in case of component device errors, the MD resynchronization
thread runs in parallel with the thrown event being processed
by the raid plugin.  The plugin retrieves the raid device status
but that still reflects insync regions as 0 (when it should
already be total regions) because the MD thread didn't update it yet.

Solution:
Remove the insync regions check and let lvconvert carry out its
pre-repair checks and optionally carry out a repair attempt.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1560739
Related:  https://bugzilla.redhat.com/show_bug.cgi?id=1468590
Related:  https://bugzilla.redhat.com/show_bug.cgi?id=1654860
Related:  https://bugzilla.redhat.com/show_bug.cgi?id=1729303
Related:  https://bugzilla.redhat.com/show_bug.cgi?id=1741016