removes the reconnect key from the database.yml generated for MySQL

The reconnect flag does not play nicely with transactions and so
it is of little use in Rails applications. Thus, albeit supported
by mysql2, it does not deserve such a prominent place in the
generated database.yml, which should be a representative config
example. Note that the flag is false by default.

Advanced users know from mysql2 docs that the flag is available.

railties/lib/rails/generators/rails/app/templates/config/databases/mysql.yml

@@ -11,10 +11,6 @@
 development:
   adapter: mysql2
   encoding: utf8
-  # It is recommended to leave reconnect disabled because automatic
-  # reconnections do not play nicely with transactions, which are
-  # used by Active Record all over the place.
-  reconnect: false
   database: <%= app_name %>_development
   pool: 5
   username: root
@@ -31,10 +27,6 @@ development:
 test:
   adapter: mysql2
   encoding: utf8
-  # It is recommended to leave reconnect disabled because automatic
-  # reconnections do not play nicely with transactions, which are
-  # used by Active Record all over the place.
-  reconnect: false
   database: <%= app_name %>_test
   pool: 5
   username: root
@@ -48,10 +40,6 @@ test:
 production:
   adapter: mysql2
   encoding: utf8
-  # It is recommended to leave reconnect disabled because automatic
-  # reconnections do not play nicely with transactions, which are
-  # used by Active Record all over the place.
-  reconnect: false
   database: <%= app_name %>_production
   pool: 5
   username: root