flapping.xfs: Do not consider entire smb2.session as knownfail

Most of the tests from smb2.session test suite passes successfully on
XFS without any extra setup. Therefore be specific about subtests which
are to be ignored due to lack of special and/or proper server setup.

Signed-off-by: Anoop C S <[email protected]>

Author: anoopcs9

testcases/smbtorture/selftest/flapping.xfs

@@ -2,4 +2,6 @@
 # samba3 which means we don't ever match with this knownfail.
 ^samba3.smb2.create.quota-fake-file
 
-^samba3.smb2.session.*
+# Ignore due to lack of proper multichannel setup.
+^samba3.smb2.session.bind2
+^samba3.smb2.session.two_logoff