cluster/afr: fixes in logic

Change-Id: Idd20b2d119448005036c6f486d93b2d0c9ee3d53
Signed-off-by: Anand Avati <avati@redhat.com>
cluster/dht: check for inode pointer in readdirp_cbk

Do not assume inode pointer will always be set in readdirp_cbk

Change-Id: I3a88f3eedd8c345f16f043abf01a0502e40d7e60
Signed-off-by: Anand Avati <avati@redhat.com>
cluster/afr: implement per-transaction-type dirty flags

Each of DATA, METADATA and ENTRY transactions now have their
own dirty flag.

Signed-off-by: Anand Avati <avati@redhat.com>
cluster/afr: implement self-heal using syncops

Signed-off-by: Anand Avati <avati@redhat.com>