[PATCH V2] xfstests: fix src/seek_sanity_test -t option

[Eric Sandeen <sandeen@redhat.com>]

_require_seek_data_hole() does not work because
the -t (test) option of seek_sanity_test is broken,
because of an early check for (argc != 2):

# src/seek_sanity_test -t foo
Usage: src/seek_sanity_test base_file_path

So _require_seek_data_hole() doesn't see the
"Kernel does not support" string it's looking for,
and passes the check.

So rather than _notrun-ing the test, it proceeds to
fail with noisy errors.

Fix that, make a common usage() function, and check for
too many args as well.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
---

V2: saner test for too many args

diff --git a/src/seek_sanity_test.c b/src/seek_sanity_test.c
index 4275a84..f957178 100644
--- a/src/seek_sanity_test.c
+++ b/src/seek_sanity_test.c
@@ -656,6 +656,12 @@ out:
 	return ret;
 }
 
+void usage(char *cmd)
+{
+	fprintf(stdout, "Usage: %s [-t] base_file_path\n", cmd);
+	exit(1);
+}
+
 int main(int argc, char **argv)
 {
 	int ret = -1;
@@ -664,23 +670,20 @@ int main(int argc, char **argv)
 	int check_support = 0;
 	int numtests = sizeof(seek_tests) / sizeof(struct testrec);
 
-	if (argc != 2) {
-		fprintf(stdout, "Usage: %s base_file_path\n", argv[0]);
-		return ret;
-	}