smbtorture: Add accented character test to flapping.cephfs

smb2.charset contains a composite character test attempting to create
accented character which is expected to fail on case insensitive CephFS
subvolumes. Therefore add the corresponding test to the flapping list
for CephFS.

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

Author: anoopcs9

testcases/smbtorture/selftest/flapping.cephfs

@@ -20,3 +20,8 @@ samba3.smb2.timestamps.time_t_1968
 # https://github.com/samba-in-kubernetes/sit-environment/pull/109
 # Note: CephFS(vfs) successfully completes smb2.session.reauth4.
 samba3.smb2.session.reauth4
+
+# Accented character test is expected to fail on case insensitive subvolumes
+# due to unicode normalization which results in same unicode character even
+# if composed using two different unicode encodings.
+^samba3.smb2.charset.*.Testing composite character \(a umlaut\)