Use <fcntl.h> instead of <sys/file.h> for open() and friends.

Delete a bunch of unnecessary #includes and sort to match style(9)
while doing the above cleanup.

ok deraadt@ krw@

client.c

@@ -17,9 +17,7 @@
  */
 
 #include <sys/types.h>
-#include <sys/file.h>
 #include <sys/socket.h>
-#include <sys/stat.h>
 #include <sys/un.h>
 #include <sys/wait.h>