Catch implicit exception

CacheBuilder.expireAfterWrite() has possibility to raise exception if
expiration is negative. So cache object cannot be set to final member in
ReplicationCache. Also its exception is not catched anywhere.

This patch moves cache creation and logging to new method.
And adds factory class for initializing ReplicationCache correctly.

Fix for JENKINS-22814: Some infomations are logged from constructor on
startup 
https://issues.jenkins-ci.org/browse/JENKINS-22814
Support for review notification levels

This is basically support for Rest API's 'notify' field on ReviewInputs.
as specified in [1].

UI changes
* Add 'Notification Level' dropdown on GerritServer allowing to
  select one the permitted values.  The default is 'ALL', which
  matches to the existing behavior of notifying all interested users.
* Add 'Notification Level' dropdown on GerritTrigger allowing to
  override the server default.

In case of multiple builds for a Gerrit event, the highest value is
chosen.

[1] https://gerrit-documentation.storage.googleapis.com/Documentation/2.7/rest-api-changes.html#set-review
Improve to treat arguments and logging
Change form value check to non-negative integer
Merge pull request #150 from rinrinne/replication-cache

Catch implicit exception
Support for review notification levels

This is basically support for Rest API's 'notify' field on ReviewInputs.
as specified in [1].

UI changes
* Add 'Notification Level' dropdown on GerritServer allowing to
  select one the permitted values.  The default is 'ALL', which
  matches to the existing behavior of notifying all interested users.
* Add 'Notification Level' dropdown on GerritTrigger allowing to
  override the server default.

In case of multiple builds for a Gerrit event, the highest value is
chosen.

[1] https://gerrit-documentation.storage.googleapis.com/Documentation/2.7/rest-api-changes.html#set-review
Merge pull request #152 from chgeo/notify-support

Support for review notification levels
[maven-release-plugin] prepare release gerrit-trigger-2.12.0-beta-2
[maven-release-plugin] prepare for next development iteration