t5700: only run with protocol version 1

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t5700-protocol-v1.sh

@@ -4,6 +4,9 @@ test_description='test git wire-protocol transition'
 
 TEST_NO_CREATE_REPO=1
 
+# This is a protocol-specific test.
+GIT_TEST_PROTOCOL_VERSION=
+
 . ./test-lib.sh
 
 # Test protocol v1 with 'git://' transport