ADF Frenetic: Fix errors with InPort and OF update ordering

See comments:
https://github.com/tnelson/frenetic/commit/d6a1630dcbcc192fec415e65d361cfcb0c529c32#diff-cad123be8a390b4f82f8fba6381e88f6R330
and 
https://github.com/tnelson/frenetic/commit/26febba99b49bb4fd6b3cde434aa40d23a24bda9#diff-ba7a1a2a92c805acd138eef31c988f07R99

Outdated version of NetCore is outdated, but I forked adferguson/frenetic to make this fix, so a pull request seems to be the right course of action.