jsonrpc: extend image over jsonrpc

Schema file was not consistend with API.py. All the verbs should use
the same constructor param names as it is defined in API.py.

Bug-Url: https://bugzilla.redhat.com/1113670
Change-Id: I676731e9a67e1a978aeb3ed298a7cfe0eea5184d
Signed-off-by: pkliczewski <piotr.kliczewski@gmail.com>