Correct microversions URL in api_plugins.rst
Correct microversions URL in api_plugins.rst

The requested URL to the microversions specific document in
api_plugins.rst is broken. Changed it to the right URL.

Change-Id: I30cf2f14d36bf7ede0a04f05b5e1e2c993403d83
Closes-Bug: #1615788

rajalokan/nova,sebrandon1/nova,sebrandon1/nova,openstack/nova,rahulunair/nova,jianghuaw/nova,mahak/nova,rajalokan/nova,mahak/nova,Juniper/nova,mikalstill/nova,jianghuaw/nova,vmturbo/nova,cloudbase/nova,vmturbo/nova,hanlind/nova,openstack/nova,gooddata/openstack-nova,rahulunair/nova,Juniper/nova,jianghuaw/nova,hanlind/nova,jianghuaw/nova,rajalokan/nova,Juniper/nova,vmturbo/nova,Juniper/nova,cloudbase/nova,alaski/nova,rajalokan/nova,phenoxim/nova,openstack/nova,rahulunair/nova,vmturbo/nova,phenoxim/nova,mikalstill/nova,klmitch/nova,hanlind/nova,alaski/nova,mahak/nova,klmitch/nova,cloudbase/nova,klmitch/nova,klmitch/nova,gooddata/openstack-nova,gooddata/openstack-nova,sebrandon1/nova,gooddata/openstack-nova,mikalstill/nova