Reverting StaticFlowEntryPusherResource.java for compatibility

The changes introduced in commit f7b5a45bdba505ab1c38c74bd42a5ace392a50f6
break Floodlight's compatibility with other applications, such as the Floodlight
circuit pusher (http://www.projectfloodlight.org/circuit-pusher/).
This commit fixes that by reverting Floodlight's StaticFlowPusher old interface.
New extensions to store and delete flows using HTTP compliant
libraries are accessible using a different URI.