Fix missing codecoverage reports (#624)

Fix travis.yml.

@jamessynge I'm skipping the code review for this one-line because I'd like to get all our other PRs back on line with coverage reports.

.travis.yml

@@ -89,6 +89,4 @@ cache:
   directories:
     - $PANDIR/astrometry/
 after_success:
-  - if [[ $TRAVIS_PYTHON_VERSION == 3.6* ]]; then
-        bash <(curl -s https://codecov.io/bash);
-    fi
+  - bash <(curl -s https://codecov.io/bash)