env: make TRAVIS_OS_NAME pull from config, not job

This is probably the cause of travis-ci/travis-ci#2205.
spec: move the 'os' variable from job to config

This fixes the broken spec from the previous commit.
Fix syntax error in specs
Android: use gradle build instead of gradle check

ref #238 and #142
Fix spec's expected number of TRAVIS_* environment variables

TRAVI_OS_NAME is no longer tested here
Merge pull request #239 from travis-ci/gc-android-gradle-defaults

Android: use gradle build instead of gradle check

Actually, I'll go ahead and merge it. It should be fine here.
Merge branch 'master' into hh-http-api
we don't need to 'fix ssl' anymore
Merge branch 'master' into hh-http-api