Get the package name right.
diff --git a/.travis/install.sh b/.travis/install.sh
index 9c6d34c..fdd7190 100755
--- a/.travis/install.sh
+++ b/.travis/install.sh
@@ -25,4 +25,4 @@
     sudo rm -rf /usr/local/pypy/bin
 fi
 
-pip install tox coverage
+pip install tox coveralls