Bug 1791

There seems a few lines are unwanted.

In bitbake/lib/bb/cooker.py, we have the followings in both BBCooker::__init__ and
BBCooker::loadConfigurationData:

if not self.configuration.cmd:
    self.configuration.cmd = self.configuration.data.getVar("BB_DEFAULT_TASK", True) or "build"

The __init__ will invoke the loadConfigurationData, so we can remove the one in the __init__.

In bitbake/lib/bb/command.py, we have the following lines:

for attr in CommandsSync.__dict__:
    command = attr[:].lower()
    method = getattr(CommandsSync, attr)
    sync_cmds[command] = (method) 

for attr in CommandsAsync.__dict__:
    command = attr[:].lower()
    method = getattr(CommandsAsync, attr)
    async_cmds[command] = (method) 

The sync_cmds and async_cmds are defined as global dictionaries, but it seems that we've never used them, it seems that they have been replaced by the self.cmds_sync and  self.cmds_async, so I think that we can remove them.