move AR4x constants to (top-level) ArJdbc

Author: kares

lib/arjdbc/jdbc.rb

@@ -2,6 +2,11 @@
 
 module ArJdbc
 
+  # @private
+  AR40 = ::ActiveRecord::VERSION::MAJOR > 3
+  # @private
+  AR42 = ::ActiveRecord::VERSION::STRING >= '4.2'
+
   class << self
 
     def warn(message, once = nil)

lib/arjdbc/mysql/adapter.rb

@@ -6,11 +6,6 @@
 module ArJdbc
   module MySQL
 
-    # @private
-    AR40 = ::ActiveRecord::VERSION::MAJOR > 3
-    # @private
-    AR42 = ::ActiveRecord::VERSION::STRING >= '4.2'
-
     require 'arjdbc/mysql/column'
     require 'arjdbc/mysql/bulk_change_table'
     require 'arjdbc/mysql/explain_support'