Fix travis-ci mac OSX builds

Author: mgreter

script/ci-install-compiler

@@ -3,4 +3,4 @@
 gem install minitest
 gem install minitap
 
-pip install --user 'requests[security]'
+pip2 install --user 'requests[security]'

script/ci-install-deps

@@ -1,7 +1,7 @@
 #!/bin/bash
 if [ "x$COVERAGE" == "xyes" ]; then
-  pip install --user gcovr
-  pip install --user cpp-coveralls
+  pip2 install --user gcovr
+  pip2 install --user cpp-coveralls
 else
   echo "no dependencies to install"
 fi