tests: Remove gpg verification files from EXTRA_DIST

Follow on from 70a11189. These files are already disted.

Closes: #372
Approved by: cgwalters

Makefile-tests.am

@@ -232,12 +232,7 @@ EXTRA_DIST += \
 	tests/libostreetest.h \
 	tests/libtest.sh \
 	tests/gpg-verify-data/README.md \
-	tests/gpg-verify-data/lgpl2 \
-	tests/gpg-verify-data/lgpl2.sig \
-	tests/gpg-verify-data/pubring.gpg \
-	tests/gpg-verify-data/secring.gpg \
-	tests/gpg-verify-data/trustdb.gpg \
-	tests/gpg-verify-data/gpg.conf
+	$(NULL)
 
 tests/libreaddir-rand.so: Makefile
 	$(AM_V_GEN) ln -fns ../.libs/libreaddir-rand.so tests