Correct exit code for dbufstat -v and arcstat -v

Both scripts were returning an error code of 1
when using the -v argument. -v should exit with
an error code of 0.

Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>

cmd/arcstat/arcstat.py

@@ -122,7 +122,7 @@ def detailed_usage():
         sys.stderr.write("%11s : %s\n" % (key, cols[key][2]))
     sys.stderr.write("\n")
 
-    sys.exit(1)
+    sys.exit(0)
 
 
 def usage():

cmd/dbufstat/dbufstat.py

@@ -143,7 +143,7 @@ def detailed_usage():
         sys.stderr.write("%11s : %s\n" % (key, cols[key][2]))
     sys.stderr.write("\n")
 
-    sys.exit(1)
+    sys.exit(0)
 
 
 def usage():