(try to) fix https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=7871

increment offset to point to the first byte after the options
(the code used to set an absolute position, if that was 0, we were stuck
 in an endless loop)

svn path=/trunk/; revision=45646

epan/dissectors/packet-clnp.c

@@ -418,7 +418,7 @@ dissect_clnp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
                          tvb, offset, clnp_tree );
   }
 
-  offset = cnf_hdr_len;
+  offset += opt_len;
 
   /* If clnp_reassemble is on, this is a segment, we have all the
    * data in the segment, and the checksum is valid, then just add the