Rename constant to a more appropriate name

Rename constant to a more appropriate name

The DB_MAX_RETRIES implies that a query will be
retried that many times. 'retry' means it happened
once before. In the current code, if DB_MAX_RETRIES
is set to 1, the query won't be retried at all.
If it's set to 0, the query won't even be run.

This constant should actually be called DB_MAX_ATTEMPTS
to indicate that the variable includes the first try.

Change-Id: I13f088ffa38c40db7fd297173e892b4ad5c7fadd