STYLE: git:// protocol is being phased out, remove it as an option

Author: dzenanz

Superbuild/Superbuild.cmake

@@ -4,12 +4,7 @@ if(NOT GIT_FOUND)
   message(ERROR "Cannot find git. git is required for Superbuild")
 endif()
 
-option( USE_GIT_PROTOCOL "If behind a firewall turn this off to use http instead." OFF)
-
-set(git_protocol "git")
-if(NOT USE_GIT_PROTOCOL)
-  set(git_protocol "https")
-endif()
+set(git_protocol "https")
 
 include( ExternalProject )