Define PRIVATE_RANGES in IPAddr class

common/lib/azure/storage/common/core/utility.rb

@@ -213,6 +213,12 @@ end
 
 # Code validate private/public IP acceptable ranges.
 class IPAddr
+  PRIVATE_RANGES = [
+    IPAddr.new('10.0.0.0/8'),
+    IPAddr.new('172.16.0.0/12'),
+    IPAddr.new('192.168.0.0/16')
+  ]
+
   def private?
     return false unless self.ipv4?
     PRIVATE_RANGES.each do |ipr|