[test-only] SPL pull request 606: ignore linux refcount_t

This patch is purely to trigger the buildbot to build and test
against SPL pull request 606:

See openzfs#5823

Requires-spl: refs/pull/606/head

Signed-off-by: Olaf Faaland <faaland1@llnl.gov>

man/man8/zdb.8

@@ -178,7 +178,8 @@ transaction type.
 .sp .6
 .RS 4n
 Read the vdev labels from the specified device. \fBzdb -l\fR will return 0 if
-valid label was found, 1 if error occured, and 2 if no valid labels were found.
+valid configuration nvlist was found, 1 if error occured, and 2 if no valid
+labels were found.
 .P
 If the \fB-u\fR option is also specified, also display the uberblocks on this
 device.