12462: Fix full-text search for terms like "foo.bar".

12462: Fix full-text search for terms like "foo.bar".

A search for a filename like "foo.bar" should match text "foo.bar" --
but "foo.bar" was transformed to "foo:* & bar:*", and since "." is a
word character, "bar:*" did not match "foo.bar".

Now "foo.bar" is transformed to "foo.bar:*".

Arvados-DCO-1.1-Signed-off-by: Tom Clegg <tclegg@veritasgenetics.com>