libext2fs: explicitly ignore a possible unlink failure in ext2fs_free_icount

There's not much we can do if the unlink of the tdb file fails, and we
don't want to print a warning message from a library.

Fixes-Coverity-Bug: 1308364
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/lib/ext2fs/icount.c b/lib/ext2fs/icount.c
index d7de19f..888a90b 100644
--- a/lib/ext2fs/icount.c
+++ b/lib/ext2fs/icount.c
@@ -89,7 +89,7 @@
 	if (icount->tdb)
 		tdb_close(icount->tdb);
 	if (icount->tdb_fn) {
-		unlink(icount->tdb_fn);
+		(void) unlink(icount->tdb_fn);
 		free(icount->tdb_fn);
 	}
 #endif