[PATCH] tests: avoid syntax triggering old dash bug

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

Avoid a bug in dash that's been fixed ever since its
ec2c84d ("[PARSER] Fix clobbering of checkkwd", 2011-03-15)[1] first
released with dash v0.5.7 in July 2011.

This fixes 1/2 tests failing on Debian Lenny & Squeeze. The other
failure is due to 1b42f45255 ("git-svn: apply "svn.pathnameencoding"
before URL encoding", 2016-02-09).

This particular test has been failing since 5f9674243d ("config: add
--expiry-date", 2017-11-18).

1. https://git.kernel.org/pub/scm/utils/dash/dash.git/

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
---
 t/t1300-config.sh | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/t/t1300-config.sh b/t/t1300-config.sh
index 9652b241c7..7690b518b8 100755
--- a/t/t1300-config.sh
+++ b/t/t1300-config.sh
@@ -892,8 +892,9 @@ test_expect_success 'get --expiry-date' '
 	1510348087
 	0
 	EOF
+	date_valid1=$(git config --expiry-date date.valid1) &&
 	{
-		echo "$rel_out $(git config --expiry-date date.valid1)"
+		echo "$rel_out $date_valid1"
 		git config --expiry-date date.valid2 &&
 		git config --expiry-date date.valid3 &&
 		git config --expiry-date date.valid4 &&
-- 
2.20.0.rc1.379.g1dd7ef354c