mds: log trimmed path wherever generating full path is necessary

mds: log trimmed path wherever generating full path is necessary

Signed-off-by: Rishabh Dave <ridave@redhat.com>
(cherry picked from commit 11de1e5772fa88125de10dc7972e0e31e33140d0)

Conflicts:
src/mds/MDSAuthCaps.cc
src/test/mds/TestMDSAuthCaps.cc
- is_capable takes one less argument in Squid compared to main branch
  version.

src/mds/Server.cc
src/mds/SessionMap.cc
-  There is lesser including of other header files in both these files
   leading to difficulty in patch application in this region.