Apply the prepared GUI security port on the current public gui branch. The complete Git tree equals candidate 9e9bb026d3d33a29a1607a1bce449e2583b1223f, built during private preparation, and includes the public v0.11.5.0 source.
f21df05 was never supposed to be merged into the master branch.
fluffypony merged #3670 before #3668 was rebased and resolved.
Note: the cherry-picked commit hashes are now invalid because #3670
was merged before #3668 was rebased with the updated repo location.
Though we only need miniupnpc, rebasing and maintaining a miniupnpc-only
repo is unrealistic.
(cherry picked from commit 3c40eb768c292a4dec79d7dffd6685fd37940a2a)