backout OCEXEC changes when potentially opening /srv files

Opening a /srv file sets the close-on-exec flag on the
shared channel breaking the exportfs openmount() hack.

The devsrv tries to prevent posting a channel with the
close-on-exec or remove-on-close flags. but nothing
currently prevents this poisoning on open.

Until this gets fixed in eigther exportfs or devsrv,
i'll back out the changes that could have potential side
effects like this.

sys/src/libauth/auth_chuid.c

@@ -29,7 +29,7 @@ auth_chuid(AuthInfo *ai, char *ns)
 	}
 
 	/* get a link to factotum as new user */
-	fd = open("/srv/factotum", ORDWR|OCEXEC);
+	fd = open("/srv/factotum", ORDWR);
 	if(fd >= 0){
 		if(mount(fd, -1, "/mnt", MREPL, "") == -1)
 			close(fd);

sys/src/libauth/newns.c

@@ -194,7 +194,7 @@ nsop(char *fn, int argc, char *argv[], AuthRpc *rpc)
 		else if(argc == 2)
 			unmount(argv[0], argv[1]);
 	}else if(strcmp(argv0, "mount") == 0){
-		fd = open(argv[0], ORDWR|OCEXEC);
+		fd = open(argv[0], ORDWR);
 		if(fd < 0){
 			if(newnsdebug)
 				fprint(2, "%s: mount: %s: %r\n", fn, argv[0]);

sys/src/libc/9sys/access.c

@@ -24,7 +24,7 @@ access(char *name, int mode)
 			return 0;
 		return -1;
 	}
-	fd = open(name, omode[mode&7]|OCEXEC);
+	fd = open(name, omode[mode&7]);
 	if(fd >= 0){
 		close(fd);
 		return 0;

sys/src/libdraw/newwindow.c

@@ -13,7 +13,7 @@ newwindow(char *str)
 	wsys = getenv("wsys");
 	if(wsys == nil)
 		return -1;
-	fd = open(wsys, ORDWR|OCEXEC);
+	fd = open(wsys, ORDWR);
 	if(fd < 0){
 		free(wsys);
 		return -1;