Remove manual installation of pysal from CI script

This shall not be needed. It may conflict with the version specified in
the setup.py and the requirements.txt files.

.travis.yml

@@ -20,9 +20,6 @@ before_install:
   - sudo apt-get -y install python-joblib=0.8.3-1-cdb1
   - sudo apt-get -y install python-numpy=1:1.6.1-6ubuntu1
 
-  # Install pysal
-  - sudo pip install -I pysal==1.11.2
-
   - sudo apt-get -y install python-scipy=0.14.0-2-cdb6
   - sudo apt-get -y --no-install-recommends install python-sklearn-lib=0.14.1-3-cdb2
   - sudo apt-get -y --no-install-recommends install python-sklearn=0.14.1-3-cdb2