packaging: spec: softened deps on websocket-proxy

Avoid to require exact version and release on websocket-proxy
just requiring an higer or equal version of it.

Change-Id: I52394107ed3b35e13746cc3e09a2b971cddaab77
Bug-Url: https://bugzilla.redhat.com/1033629
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>