smb3: remove per-session operations from per-tree connection stats

smb3: remove per-session operations from per-tree connection stats

Remove counters from the per-tree connection /proc/fs/cifs/Stats
output that will always be zero (since they are not per-tcon ops)
ie SMB3 Negotiate, SessionSetup, Logoff, Echo, Cancel.

Also clarify "sent" to be "total" per-Pavel's suggestion
(since this "total" includes total for all operations that we try to
send whether or not succesffully sent). Sample output below:

Resources in use
CIFS Session: 1
Share (unique mount targets): 2
SMB Request/Response Buffer: 1 Pool size: 5
SMB Small Req/Resp Buffer: 1 Pool size: 30
Operations (MIDs): 0

1 session 2 share reconnects
Total vfs operations: 23 maximum at one time: 2

1) \\localhost\test
SMBs: 45
TreeConnects: 2 total 0 failed
TreeDisconnects: 0 total 0 failed
Creates: 13 total 2 failed
Closes: 9 total 0 failed
Flushes: 0 total 0 failed
Reads: 0 total 0 failed
Writes: 1 total 0 failed
Locks: 0 total 0 failed
IOCTLs: 3 total 1 failed
QueryDirectories: 4 total 2 failed
ChangeNotifies: 0 total 0 failed
QueryInfos: 10 total 0 failed
SetInfos: 3 total 0 failed
OplockBreaks: 0 sent 0 failed

Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>