Requests 1.0 makes a backwards incompatible API change

Requests json changed from dict to a function.  This broke the pool manager
when talking the admin API.

Also the version number of the admin API was not incremented as specified so
switch back to 'v1'.

Fixes bug #1096846

Change-Id: I0a296ba8c4397f56d435e71b88c93c041c9a82df