Revert "Updating the virgo-build submodule to use https instead of git"

This reverts commit f3e607e8cbb7b28489ba46a9f6c30263e18575e4.
diff --git a/.gitmodules b/.gitmodules
index 4b37206..1f9ea18 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,3 @@
 [submodule "virgo-build"]
 	path = virgo-build
-	url = https://git.eclipse.org/gitroot/virgo/org.eclipse.virgo.virgo-build.git
+	url = git://git.eclipse.org/gitroot/virgo/org.eclipse.virgo.virgo-build.git