Improve handling of unsupported security policies

* If the server asks for more than we can support, don't throw
  and error from PolicySet creation.  Let isSupported() do that.
* Overlong password lengths cannot be supported and isSupported is false.
* Overlong timeouts & max wipes can be reduced to supported
  amount (this actually increases security) and isSupported is true.
* Clean up an obsolete comment
* Unit tests

Bug: 2567804
Change-Id: I2d664a7f2a315b9f9bdcb867fe2cd98f74de6f66
1 file changed