Re-initialize error after attach

If flag for error after attach is not reinitialized, it may cause
NullPointerException on subsequent onAttachedWindow if error text
was reset to null.

Change-Id: I8976c28a6ca71017e5c4b3f29d4eeeb2eda48c38
CompoundButton: Let text can be changed by config

Because CompoundButton freezes text inside onSaveInstanceState, the text
can't be changed automatically after locale of device changed.
Bug from such a case reported via url below:
https://code.google.com/p/android/issues/detail?id=24013

It would be better to don't freeze text for default case and let users
to freeze text if they need manually.

Change-Id: I2d6a192b6ff05a95b21487c2362cbc14691c68cf
Signed-off-by: SeongJae Park <sj38.park@gmail.com>