Revert "Summary: Problem: Android build fails due to use of JCenter"
Revert "Summary: Problem: Android build fails due to use of JCenter"

2 reasons:

- Former PR is incomplete and breaks "release" Android build system.
"snapshot" builds are not impacted.
- Jcenter/Bintray are back in service, after outage.

This reverts commit 8768c80f6e7ab42b24e577655db59acf81d2e0d2.

zeromq/zproject,zeromq/zproject,zeromq/zproject