Instal sleekxmpp using pip

.travis.yml

@@ -1,4 +1,6 @@
 language: cpp
+python:
+  - "2.7"
 sudo: required
 dist: trusty
 virtualenv:
@@ -8,7 +10,7 @@ before_script:
           - echo "deb http://swift.im/packages/ubuntu/trusty development main" | sudo tee -a /etc/apt/sources.list
           - sudo apt-get update -qq
           - sudo apt-get install -y --force-yes ngircd libswiften-dev libprotobuf-dev protobuf-compiler pidgin-dev liblog4cxx10-dev libpopt-dev libboost-dev libboost-signals-dev libboost-system-dev libboost-thread-dev libboost-filesystem-dev libboost-program-options-dev libboost-regex-dev libboost-date-time-dev libcppunit-dev
-          - sudo pip install sleekxmpp
+install: "pip install sleekxmpp"
 script:
           - cmake -DCMAKE_BUILD_TYPE=Debug -DENABLE_TESTS=ON . && make libtransport_test && ./src/libtransport_test && cd ./spectrum/src/tests && python -V && python irc_test.py
 notifications: