Use same xulrunner SDK directory for all platforms

Change-Id: I31c54e80d9dd97e3c634577205e9ed5de4788dbe

vendorsetup.sh

@@ -260,18 +260,9 @@ else
    esac
 fi
 
-if [ `uname` == 'Darwin' ]; then
-   XULRUNNER_DIRECTORY="$(gettop)/xulrunner-sdk-mac"
-else
-   XULRUNNER_DIRECTORY="$(gettop)/xulrunner-sdk-linux"
-fi
-
-# Use a local Xulrunner SDK copy instead of downloading
-if [[ -d ${XULRUNNER_DIRECTORY}/.git ]]; then
+# Use a local xulrunner SDK if present instead of downloading a new copy
+if [[ -d gaia/xulrunner-sdk/.git ]]; then
    export USE_LOCAL_XULRUNNER_SDK=1
-   export XULRUNNER_DIRECTORY
-else
-   unset XULRUNNER_DIRECTORY
 fi
 
 # Don't build sources.xml