Change testing strategy. No idea why it fixes missing libexpat (#12)

Fixes:
ImportError: libexpat.so.0: cannot open shared object file: No such file or directory

On x86_64 manylinux1 test runs

Author: wiktorn

config.sh

@@ -81,5 +81,5 @@ function run_tests {
     fi
     python --version
     cd ../pyosmium/test
-    python -m nose
+    python -m nose test*py
 }