Worked around that connection can't be reset if allow_concurrency is off. Closes #2648.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2816 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

activerecord/CHANGELOG

 *SVN*
 
+* Worked around that connection can't be reset if allow_concurrency is off.  #2648 [Michael Schoen <schoenm@earthlink.net>]
+
 * Fixed SQL Server adapter to pass even more tests and do even better #2634 [rtomayko@gmail.com]
 
 * Fixed SQL Server adapter so it honors options[:conditions] when applying :limits #1978 [Tom Ward]

activerecord/lib/active_record/connection_adapters/abstract/connection_specification.rb

@@ -109,6 +109,7 @@ def self.remove_connection(klass=self)
       conn = @@defined_connections[klass]
       @@defined_connections.delete(klass)
       active_connections[klass] = nil
+      @connection = nil
       conn.config if conn
     end