Deallocate ip if build fails.

Fixes LP837687

Change-Id: I7c0ea900225024e69a0265c430724930ce7b892d

run_tests.sh

@@ -89,8 +89,23 @@ function run_pep8 {
   srcfiles+=" `find tools/*`"
   srcfiles+=" nova setup.py plugins/xenserver/xenapi/etc/xapi.d/plugins/glance"
   # Just run PEP8 in current environment
+  #
+  # NOTE(sirp): W602 (deprecated 3-arg raise) is being ignored for the
+  # following reasons:
+  #
+  #  1. It's needed to preserve traceback information when re-raising
+  #     exceptions; this is needed b/c Eventlet will clear exceptions when
+  #     switching contexts.
+  #
+  #  2. There doesn't appear to be an alternative, "pep8-tool" compatible way of doing this
+  #     in Python 2 (in Python 3 `with_traceback` could be used).
+  #
+  #  3. Can find no corroborating evidence that this is deprecated in Python 2
+  #     other than what the PEP8 tool claims. It is deprecated in Python 3, so,
+  #     perhaps the mistake was thinking that the deprecation applied to Python 2
+  #     as well.
   ${wrapper} pep8 --repeat --show-pep8 --show-source \
-    --ignore=E202 \
+    --ignore=E202,W602 \
     --exclude=vcsversion.py ${srcfiles}
 }