core: improve logs in several classes

remove class name from log statement because it's logged anyway
switch from errorFormat to error when there are no parameters to fill
fix mispelling (VSD to VDS)

Change-Id: Id15f1c19f20c7dbd67f4bfa804840f9de9757bf2
Signed-off-by: Alissa Bonas <abonas@redhat.com>