[gegl] tests: update clean target in mipmap tests makefile

[Øyvind Kolås <ok src gnome org>]

commit 0da216502c77dbcdb5cc0cee417a08229c288930
Author: Øyvind Kolås <pippin gimp org>
Date:   Mon Jan 30 22:54:35 2017 +0100

    tests: update clean target in mipmap tests makefile

 tests/mipmap/Makefile.am |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/tests/mipmap/Makefile.am b/tests/mipmap/Makefile.am
index d323464..cb3e2da 100644
--- a/tests/mipmap/Makefile.am
+++ b/tests/mipmap/Makefile.am
@@ -10,4 +10,4 @@ check-TESTS: $(TESTS)
          $(TESTS)
 
 clean-local:
-       rm -f test-exp-combine.hdr test-exp-combine-diff.png
+       rm -f *-output.png