post-review fixes

include/my_sys.h:
  added prototype for the defaults correction function
libmysql/Makefile.shared:
  my_chsize added to libmysql to let my_correct_defaults_file be used from libmysql
mysys/default.c:
  New defaults function added we use it to correct defaults file. Currently the function doesn't lock defaults
  file. This is because of the linking and backwards-compatibility issues. This needs to be fixed later.
mysys/my_chsize.c:
  comment added
server-tools/instance-manager/buffer.cc:
  cleanup
server-tools/instance-manager/commands.cc:
  refactoring: removed do_command method from most of the classes
server-tools/instance-manager/commands.h:
  cleanup
server-tools/instance-manager/guardian.cc:
  cleanup
server-tools/instance-manager/instance.cc:
  cleanup
server-tools/instance-manager/instance_map.cc:
  cleanup
server-tools/instance-manager/instance_options.cc:
  cleanup
server-tools/instance-manager/instance_options.h:
  cleanup
server-tools/instance-manager/listener.cc:
  cleanup
server-tools/instance-manager/log.cc:
  cleanup
server-tools/instance-manager/manager.cc:
  cleanup
server-tools/instance-manager/messages.cc:
  new errors added
server-tools/instance-manager/mysql_connection.cc:
  cleanup
server-tools/instance-manager/mysql_manager_error.h:
  new error codes added
server-tools/instance-manager/mysqlmanager.cc:
  clenup
server-tools/instance-manager/options.cc:
  cleanup
server-tools/instance-manager/parse.cc:
  removed unused function
server-tools/instance-manager/parse.h:
  removed prototype
server-tools/instance-manager/protocol.cc:
  cleanup
server-tools/instance-manager/protocol.h:
  added enum to be used in protocol.cc instead of the constants

server-tools/instance-manager/protocol.h

@@ -25,6 +25,9 @@ typedef struct field {
   uint length;
 } NAME_WITH_LENGTH;
 
+/* default field length to be used in various field-realted functions */
+enum { DEFAULT_FIELD_LENGTH= 20 };
+
 struct st_net;
 
 int net_send_ok(struct st_net *net, unsigned long connection_id,