[gstreamermm] Fix distclean build

[Marcin Kolny <mkolny src gnome org>]

commit 1cdabc41c4fc677991ccd10b743d507a8192985f
Author: Marcin Kolny <marcin kolny gmail com>
Date:   Sat Oct 21 12:47:44 2017 +0100

    Fix distclean build

 tests/Makefile.am |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 1d931a9..b2451cd 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -19,6 +19,8 @@ AM_CPPFLAGS = -I$(top_builddir) -I$(srcdir) $(gstreamermm_includes) $(GSTREAMERM
 AM_CXXFLAGS = $(GSTREAMERMM_WXXFLAGS) -g -Wno-missing-field-initializers
 LDADD = $(GSTREAMERMM_LIBS) $(local_libgstreamermm) -lgtest -lpthread
 
+CLEANFILES = test-integration-bininpipeline-output-image.jpg
+
 check_PROGRAMS =                                \
         test-allocator                          \
         test-atomicqueue                        \