removal of no-cache-dir flag

Author: cmccarthy1

.travis.yml

@@ -27,7 +27,7 @@ script:
     echo -n $QLIC_KC |base64 --decode > q/kc.lic;
     pip install --upgrade pip;
     pip install --upgrade setuptools;
-    pip -q install -r tests/requirements.txt --no-cache-dir;
+    pip -q install -r tests/requirements.txt;
     q test.q -s 4 -q;
   else
     echo No kdb+, no tests;