travis-ci: Explicitly install Cython before pandas
diff --git a/.travis.yml b/.travis.yml
index ac8c99c..ba3b23c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,6 +9,7 @@
   - sudo dpkg -i trace-cmd_2.4.0-1_amd64.deb
 install:
   - pip install matplotlib
+  - pip install Cython --install-option="--no-cython-compile"
   - pip install pandas
   - pip install ipython[all]
 env: