Enable release notes translation

Releasenote translation publishing is being prepared. 'locale_dirs'
needs to be defined in conf.py to generate translated version of the
release notes.

Note that this repository might not get translated release notes - or
no translations at all - but we add the entry here nevertheless to
prepare for it.

Change-Id: Ib265f919e176f048f6e56bde47db3d99b3dd993e

Author: ajaeger

releasenotes/source/conf.py

@@ -300,3 +300,6 @@
 
 # If true, do not generate a @detailmenu in the "Top" node's menu.
 # texinfo_no_detailmenu = False
+
+# -- Options for Internationalization output ------------------------------
+locale_dirs = ['locale/']