t1016: make sure to use specified GPG

c348192a (t1016: clean up style, 2024-10-22) fixed a coding style
violation that has an extra space between redirection operator ">"
and the redirection target, but at the same time, replaced the use
of "git config" to set a configuration variable to be used by the
remainder of tests with "test_config".  The pattern employed here is
that the first set-up test prepares the environment to be used by
subsequent tests, which then use the settings left by this set-up
test to perform their tasks.  Using test_config in the first set-up
test means the config setting made by the set-up test is reverted at
the end of the first set-up test, which totally misses the point.

Go back to use "git config" to fix this.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1016-compatObjectFormat.sh

@@ -116,7 +116,7 @@ do
 		git config core.repositoryformatversion 1 &&
 		git config extensions.objectformat $hash &&
 		git config extensions.compatobjectformat $(compat_hash $hash) &&
-		test_config gpg.program $TEST_DIRECTORY/t1016/gpg &&
+		git config gpg.program $TEST_DIRECTORY/t1016/gpg &&
 		echo "Hello World!" >hello &&
 		eval hello_${hash}_oid=$(git hash-object hello) &&
 		git update-index --add hello &&