Don't run bashate on output directories

Ignore output directories when running bashate to make it
easier to run the tests on an active repo.

Change-Id: I07ce0d9e3d7946048fa3743c68d2222884923866

tox.ini

@@ -8,5 +8,9 @@ deps = {env:BASHATE_INSTALL_PATH:bashate==0.5.1}
 whitelist_externals = bash
 commands = bash -c "find {toxinidir} \
                     -not \( -type d -name .?\* -prune \) \
+                    -not \( -type d -name output-\* -prune \) \
+                    -not \( -type d -name overlay-\* -prune \) \
+                    -not \( -type d -name buildroot -prune \) \
+                    -not \( -type d -name download -prune \) \
                     -type f -name \*.sh \
                     -print0 | xargs -0 bashate -v -iE002,E003,E010,E011"