chore(compat): another attempt to get travis right

Author: Byron

.travis.yml

@@ -8,7 +8,7 @@ python:
   # - "pypy" - won't work as smmap doesn't work (see gitdb/.travis.yml for details)
 matrix:
   allow_failures:
-    python: "2.6"
+    - python: "2.6"
 git:
   # a higher depth is needed for most of the tests - must be high enough to not actually be shallow
   # as we clone our own repository in the process

doc/source/intro.rst

@@ -14,7 +14,8 @@ Requirements
 ============
 
 * `Python`_ 2.7 or newer
-    Since GitPython 2.0.0
+    Since GitPython 2.0.0. Please note that python 2.6 is still reasonably well supported, but might
+    deteriorate over time.
 * `Git`_ 1.7.0 or newer
     It should also work with older versions, but it may be that some operations
     involving remotes will not work as expected.