utils: fix endless write of resize event

issue introduced with c82166afabd63f6271990be89ffa6609d3dc6712

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

cmd/podman/utils.go

@@ -182,6 +182,7 @@ func resizeTty(ctx context.Context, resize chan remotecommand.TerminalSize) {
 				case <-sigchan:
 					resizeEvent = getResize()
 				case resize <- *resizeEvent:
+					resizeEvent = nil
 				}
 			}
 		}