Remove incorrect setting of errno = EBADF when a select() has data or eof on read fds
and no data is waiting on error fds.

Reference: /n/sources/patch/applied/ape-select
Date: Thu Feb 28 23:44:23 CET 2013
Signed-off-by: jas@corpus-callosum.com

--- /sys/src/ape/lib/ap/plan9/_buf.c	Thu Feb 28 23:40:43 2013
+++ /sys/src/ape/lib/ap/plan9/_buf.c	Thu Feb 28 23:40:41 2013
@@ -292,12 +292,6 @@
 				if(_startbuf(i) != 0) {
 					return -1;
 				}
-			b = f->buf;
-			if(rfds && FD_ISSET(i,rfds) && b->eof && b->n == 0)
-			if(efds == 0 || !FD_ISSET(i,efds)) {
-				errno = EBADF;		/* how X tells a client is gone */
-				return -1;
-			}
 		}
 
 	/* check wfds;  for now, we'll say they are all ready */