The of<version#> protocol is not listed in the filter names list

[bjeremy]

I cloned the repo from master and built as instructed, but encountered a problem. If I explicilty sniff an openflopw interface (via tcp.port) I can capture the messages and the dissector will work, however selecting the filter name 'of' will not capture any packets. If I select of12.whatever_header_item, this also was recognized.

After some searching I came across this:
http://seclists.org/wireshark/2013/Aug/297

The above contains code to add to the openflow-common.cpp file to add items to the protocol tree. After the patch, filtering on just 'of' will capture all ofp version packets however only 1.2 and 1.3 versions are seem to be dissected. Adding this to the code in master may alleviate some initial confusion people may have with the dissector. (I'm actually embarassed to admit how much time I spent on this issue.)