Fix Oracle installation SQL

The starting and minimal values of sequences on Oracle are both '1' by
default. We want a user with id of 0 (used for anonymous edits), so
these were both set to '0' and the user was inserted with its id being
the next value in the sequence.

However, due to some low level caching settings you can miss the first
value in a sequence. It makes no difference to other sequences, but it
does with this one, as it must be 0 to maintain foreign key validity.
Therefore let's just set the sequence to default starting value of '1'
and insert the user with hardcoded id=0.

Bug: 38411
Change-Id: Ic9a17b92d6052fbdc24dd431726e4d82dbf48034