bug in nmh XOAUTH2 support fixed

[David Levine]

If you use XOAUTH2 to send or receive to/from Gmail's SMTP/POP3
servers using XAUTH2, this might affect you.  There was a bug
that could cause post(1) and inc(1) to crash if you have 4 or
more accounts in your oauth-gmail file.  I just committed a fix:

Fixed memory corruption in post(1) and inc(1) when using XOAUTH2.

An internal table for the oauth entries was initially sized at
4, and then reallocated if the user has 4 or more.  However,
the reallocation didn't account for the size of the allocated
structure.

Also, increased the initial size to 16, trading off slightly
increased memory usage for performance.

David