Set the COL_PROTOCOL column to "ISIS" in the ISIS dissector, rather than

Set the COL_PROTOCOL column to "ISIS" in the ISIS dissector, rather than
in its caller.

Set the COL_PROTOCOL column to "COTP" in the COTP dissector, rather than
in the dissectors it calls, so that it's done for all frames we hand to
that dissector.

Set the COL_INFO field for COTP packets we don't dissect because the
length indicator is zero, or the frame is too short, or the PDU type is
bogus.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@1842 f5534014-38df-0310-8fa8-9805f1628bb7