Remove unused .travis.yml file.

It wouldn't be very nice to test this on Travis for three versions of
Python, because some of the integration tests generate keys, and
although this is usually done with a UID comment saying `(INSECURE!)`
in order to trigger libgcrypt's use of the dummy RNG, the testing
process is still a little brutal on heavily used headless machines.

.travis.yml

@@ -1,12 +0,0 @@
-language: python
-before_install:
-  - sudo apt-get install gpg
-python:
-  - "2.6"
-  - "2.7"
-  - "3.3"
-install:
-  - make install
-# command to run tests, e.g. python setup.py test
-script:
-  - make test