Refactor: fencer: Drop XML patchset logging

The call to xml_apply_patchset() also trace-logs the patchset.

Also revert most of aea44d61. There's an obvious error when setting the
rc variable (although it works since false == 0 == pcmk_rc_ok).
Additionally, the relocation of a block of code in that commit is no
longer necessary.

Signed-off-by: Reid Wahl <nrwahl@protonmail.com>