remove older api doc

api referance doc uses api-ref and adds microversion history.

Change-Id: I654bd25966f0f5ef982928766ac58aced2bc784c

watcher/api/controllers/rest_api_version_history.rst

@@ -0,0 +1,27 @@
+REST API Version History
+========================
+
+This documents the changes made to the REST API with every
+microversion change. The description for each version should be a
+verbose one which has enough information to be suitable for use in
+user documentation.
+
+1.0 (Initial version)
+-----------------------
+This is the initial version of the Watcher API which supports
+microversions.
+
+A user can specify a header in the API request::
+
+  OpenStack-API-Version: infra-optim <version>
+
+where ``<version>`` is any valid api version for this API.
+
+If no version is specified then the API will behave as if version 1.0
+was requested.
+
+1.1
+---
+Added the parameters ``start_time`` and ``end_time`` to
+create audit request. Supported for start and end time of continuous
+audits.