Remove Ruby 1.9.2 from Travis runs

This started failing on 1.9.2 and there's little incentive to fix it.

Change-Id: I50997be1fea36a51ac322dd714fc076558a4c33b
Reviewed-on: http://gerrit.causes.com/38448
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>

Author: Shane da Silva

.travis.yml

@@ -1,6 +1,5 @@
 rvm:
   - 1.8.7
-  - 1.9.2
   - 1.9.3
   - 2.0.0
   - 2.1.0

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 * Fix bug where `CHERRY_PICK_HEAD` would be lost when a pre-commit hook failed
   after attempting to cherry pick a commit with a conflict
+* Drop support for Ruby 1.9.2
 
 ## 0.11.0
 

README.md

@@ -33,7 +33,6 @@ about Overcommit on our [engineering blog](http://causes.github.io).
 The following Ruby versions are supported:
 
 * 1.8.7
-* 1.9.2
 * 1.9.3
 * 2.0.0
 * 2.1.0