Make oslosphinx requirement optional

There is a build cycle between reno and oslosphinx. Now the
documentation can be build without oslosphinx installed.

Change-Id: Iae6abbe5b2991123f56bf2f4e852c57cd9ca6c11

doc/source/conf.py

@@ -15,6 +15,16 @@
 import os
 import sys
 
+# oslosphinx uses reno and reno uses oslosphinx. Make oslosphinx for
+# reno optional to break the build cycle
+try:
+    import oslosphinx
+except:
+    has_oslosphinx = False
+else:
+    has_oslosphinx = True
+
+
 sys.path.insert(0, os.path.abspath('../..'))
 # -- General configuration ----------------------------------------------------
 
@@ -23,10 +33,12 @@ sys.path.insert(0, os.path.abspath('../..'))
 extensions = [
     'sphinx.ext.autodoc',
     #'sphinx.ext.intersphinx',
-    'oslosphinx',
     'reno.sphinxext',
 ]
 
+if has_oslosphinx:
+    extensions.append('oslosphinx')
+
 # autodoc generation is a bit aggressive and a nuisance when doing heavy
 # text edit cycles.
 # execute "export SPHINX_DEBUG=1" in your terminal to disable

releasenotes/notes/optional-oslosphinx-55843a7f80a14e58.yaml

@@ -0,0 +1,5 @@
+---
+other:
+  - The oslosphinx dependency for building documentation
+    is now optional. This breaks a build cycle between
+    oslosphinx and reno.