Fix busted release notes

A bad release note slipped through because the bash script
wasn't returing the actual results. This fixes the script
and the busted release note.

Change-Id: Id32557f34121fe82fac21d089e4117a72ff585e5
Closes-Bug: #1610312

releasenotes/notes/instance-path-2efca507456d8a70.yaml

@@ -1,10 +1,13 @@
 ---
 upgrade:
-  - Prior to Grizzly release default instance directory names were based on
+  - |
+    Prior to Grizzly release default instance directory names were based on
     instance.id field, for example directory for instance could be named
     ``instance-00000008``. In Grizzly this mechanism was changed,
     instance.uuid is used as an instance directory name, e.g. path to instance:
+
     ``/opt/stack/data/nova/instances/34198248-5541-4d52-a0b4-a6635a7802dd/``.
+
     In Newton backward compatibility is dropped. For instances that haven't
     been restarted since Folsom and earlier maintanance should be scheduled
     before upgrade(stop, rename directory to instance.uuid, then start) so Nova

tools/releasenotes_tox.sh

@@ -6,6 +6,7 @@ sphinx-build -a -E -W \
     -d releasenotes/build/doctrees \
     -b html \
     releasenotes/source releasenotes/build/html
+BUILD_RESULT=$?
 
 UNCOMMITTED_NOTES=$(git status --porcelain | \
     awk '$1 == "M" && $2 ~ /releasenotes\/notes/ {print $2}')