testing/fstest/fstest_main.c: Eliminate a warning found during the build
test.
@@ -1084,7 +1084,8 @@ int main(int argc, FAR char *argv[])
/* Perform garbage collection, integrity checks */
- fstest_gc(buf.f_bfree);
+ ret = fstest_gc(buf.f_bfree);
+ UNUSED(ret);
/* Show memory usage */
