Fix more phrase bugs

1.  When searching across multiple fields with different boosts terms used
to get the max weight and phrases the specific weight.  Now they all get
the max weight.
2.  Phrases score used to not include the default similarity portion of the
score.

I'm not happy with how much code was required for this.  Most of it was for
bug number 2.

Change-Id: Ib7284e924e9ee5f446a2ebf192ff5fc48028a3aa
Merge "Fix more phrase bugs"