Fix appservers selecting the same port#3216

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whoarethebritons wants to merge 4 commits intoAppScale:masterfrom

whoarethebritons:check-port-usage

Commits on Nov 7, 2019

Commits on Nov 13, 2019

Merge branch 'master' of http://github.com/AppScale/appscale into check-port-usage
whoarethebritons
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Commits on Nov 15, 2019

add unit test to get distinct ports and fix excluded port initialization
whoarethebritons
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