Merge "tox testing fails if no files match search criteria"

tox.ini

@@ -21,12 +21,12 @@ commands =
          -not -name \*~                       \
          -not -name \*.md                     \
          -name \*.sh                          \
-         -print0 | xargs -0 bashate -v"
+         -print0 | xargs -0 --no-run-if-empty bashate -v"
   bash -c "find {toxinidir}        \
             \( -name middleware/io-monitor/recipes-common/io-monitor/io-monitor/io_monitor/test-tools/yaml/* -prune \) \
             -o \( -name .tox -prune \)         \
             -o -type f -name '*.yaml'       \
-            -print0 | xargs -0 yamllint"
+            -print0 | xargs -0 --no-run-if-empty yamllint"
 
 [testenv:pep8]
 usedevelop = False