Per comments in Jira, be explicit about what collector we
use. Existing code simply hard-codes HBASE_OPTS in
`conf/hbase-env.sh`. We now need to be a little more clever than this,
so moves the definition into `bin/hbase`. Also consolidates logic
around JVM version detection into a reusable function.
This change also changes how we set `HBASE_OPTS`. Before, we would
accept an operator's value, but always append our GC
prescription. After this change, we defer entirely to the operator's
choice, only applying our values when they've not specified their
intentions.
Signed-off-by: stack <stack@apache.org>
Signed-off-by: Sean Busbey <busbey@apache.org>