Revert "re add postgres to the mix"

This reverts commit ecf77b6a.

.travis.yml

@@ -9,9 +9,9 @@ rvm:
   - 1.9.2
 
 env:
-  - DB=postgres BUILD_TYPE=other
+  # - DB=postgres BUILD_TYPE=other
   - DB=mysql BUILD_TYPE=other
-  - DB=postgres BUILD_TYPE=cucumber
+  # - DB=postgres BUILD_TYPE=cucumber
   - DB=mysql BUILD_TYPE=cucumber
 
 before_install: