t1300: remove duplicate test for `--file no-such-file`

We test that we can handle `git config --file symlink` and the error
case of `git config --file symlink-to-missing-file`. For good measure,
we also throw in a test to check that we correctly handle referencing a
missing regular file. But we have such a test earlier in this script.
They both check that we fail to use `--file no-such-file --list`.

Drop the latter of these and keep the one that is in the general area
where we test `--file` and `GIT_CONFIG`. The one we're dropping also
checks that we can't even get a specific key from the missing file --
let's make sure we check that in the test we keep.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1300-config.sh

@@ -469,7 +469,8 @@ test_expect_success 'new variable inserts into proper section' '
 '
 
 test_expect_success 'alternative --file (non-existing file should fail)' '
-	test_must_fail git config --file non-existing-config -l
+	test_must_fail git config --file non-existing-config -l &&
+	test_must_fail git config --file non-existing-config test.xyzzy
 '
 
 cat > other-config << EOF
@@ -1032,11 +1033,6 @@ test_expect_success SYMLINKS 'symlinked configuration' '
 	test_cmp expect actual
 '
 
-test_expect_success 'nonexistent configuration' '
-	test_must_fail git config --file=doesnotexist --list &&
-	test_must_fail git config --file=doesnotexist test.xyzzy
-'
-
 test_expect_success SYMLINKS 'symlink to nonexistent configuration' '
 	ln -s doesnotexist linktonada &&
 	ln -s linktonada linktolinktonada &&