libjaylink: use http mirror for submodule

The other submodules default to http for users behind firewalls.

Change-Id: I58fce00478ec6c94f75992f4e8f0c24f556abe61
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/3172
Tested-by: jenkins

.gitmodules

@@ -6,4 +6,4 @@
 	url = http://repo.or.cz/r/jimtcl.git
 [submodule "src/jtag/drivers/libjaylink"]
 	path = src/jtag/drivers/libjaylink
-	url = git://repo.or.cz/libjaylink.git
+	url = http://repo.or.cz/r/libjaylink.git