Fix 'Module index' broken HTTP link

'Module Index' link points to HTML doc generated from source/api
RST files. These RST files are generated by pbr, by setting the
parameter 'autodoc_index_modules' to True.

Partial-Bug: #1535244
Change-Id: Ifceb5a140599d3968ea3d353b12c0bbe99d955e6

watcher/decision_engine/planner/base.py

@@ -53,8 +53,8 @@ class BasePlanner(object):
         :param solution: the solution given by the strategy to
         :param audit_uuid: the audit uuid
         :return: ActionPlan ordered sequence of change requests
-        such that all security, dependency,
-        and performance requirements are met.
+            such that all security, dependency, and performance
+            requirements are met.
         """
         # example: directed acyclic graph
         raise NotImplementedError()