CLT.version: check 10.9 CLT first

10.9 users might have older CLT receipts sitting around, which could
result in bad pkgutil results. For example, before changing this, my
`brew --config` was printing '1.0' (the 10.7 version) instead of
'5.0.1.0.1.1382131676', the actual CLT I had installed.

Library/Homebrew/os/mac/xcode.rb

@@ -218,7 +218,7 @@ module OS
       end
 
       def detect_version
-        [STANDALONE_PKG_ID, FROM_XCODE_PKG_ID, MAVERICKS_PKG_ID].find do |id|
+        [MAVERICKS_PKG_ID, STANDALONE_PKG_ID, FROM_XCODE_PKG_ID].find do |id|
           version = MacOS.pkgutil_info(id)[/version: (.+)$/, 1]
           return version if version
         end