test: Fix make target check-report.tap

Fix a fat-fingered invocation of tap-merge.pl in the recipe of target
check-report.tap.

Fixes: 9df43317b82 "test: replace gtester with a TAP driver"
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20190604080010.23186-1-armbru@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
diff --git a/tests/Makefile.include b/tests/Makefile.include
index 46a36c2..34df040 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -904,7 +904,7 @@
 # Reports and overall runs
 
 check-report.tap: $(patsubst %,check-report-qtest-%.tap, $(QTEST_TARGETS)) check-report-unit.tap
-	$(call quiet-command,./scripts/tap-merge.py $^ > $@,"GEN","$@")
+	$(call quiet-command, cat $^ | scripts/tap-merge.pl >$@,"GEN","$@")
 
 # FPU Emulation tests (aka softfloat)
 #