submodules: fix url for winsparkle

till the directory exists or this will break submodule fetch

.gitmodules

+[submodule "winsparkle"]
+    path = winsparkle
+    url = git://github.com/vslavik/winsparkle.git
+    ignore = dirty
 [submodule "libqrencode"]
     path = libqrencode
     url = https://github.com/fukuchi/libqrencode.git