b/17720266
When replying to a message, sometimes the wrong message
is included in the reply. This seems to be related to
smart reply/forward, since it only has ever been known to
happen on an Exchange 2013 server. For now, disable smart
reply/forward.
We do this by making the EmailProvider always zero out the
FLAGS_SUPPORTS_SMART_FORWARD bit on the account. This way
we can control this feature from the Email app, rather than
Exchange.
Change-Id: I88bb5f06a1098f9f085592b0a3cf1a01d9eb3fc7