jsonrpc: remove pointless 'continue' statement

This was left behind in commit 122e28465 ("jsonrpc: move closed conn
handling before poll()").  It is not needed now that the closed
connection handling is in a loop by itself.

Change-Id: I09959003bc6a370f1621815aebdd428be3304e5e
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/369906
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>

lib/jsonrpc/jsonrpc_server_tcp.c

@@ -362,8 +362,6 @@ spdk_jsonrpc_server_poll(struct spdk_jsonrpc_server *server)
 				SPDK_TRACELOG(SPDK_TRACE_RPC, "all outstanding requests completed\n");
 				spdk_jsonrpc_server_conn_remove(conn);
 			}
-
-			continue;
 		}
 	}