Fix errors against latest Gerrit core

Fix breakage due to a core change (Ifc8316278) which tries to avoid
the usage of ChangeIndex and removes createChecked(Change.Id) method.
Due to which the build for the tip version of batch plugin fails.

Also bump WORKSPACE/pom to 3.3.1 so that in-tree and out-of-tree builds are
in sync.

Change-Id: I03b79282804d23bdab74ef575dcb4a28d1e68c77
4 files changed