fix reference to EsriToken, avoid using rails .minutes

lib/geocoder/esri_token.rb

@@ -30,7 +30,7 @@ module Geocoder
         Geocoder.log(:warn, response['error'])
       else
         token_value = response['access_token']
-        expires_at = Time.now + expires.minutes
+        expires_at = Time.now + (expires * 60)
         new(token_value, expires_at)
       end
     end

lib/geocoder/lookups/esri.rb

@@ -51,7 +51,7 @@ module Geocoder::Lookup
       if configuration[:token] && configuration[:token].active? # if we have a token, use it
         configuration[:token].to_s
       elsif configuration.api_key # generate a new token if we have credentials
-        token_instance = EsriToken.generate_token(*configuration.api_key)
+        token_instance = Geocoder::EsriToken.generate_token(*configuration.api_key)
         Geocoder.configure(:esri => {:token => token_instance})
         token_instance.to_s
       end