Fix declaration of ForeignDBFile::delete()

Strict Standards: Declaration of ForeignDBFile::delete() should be
compatible with that of LocalFile::delete()

Followed-Up: I60cab27e0708a818c77791cc89194b6dd726da0b
Change-Id: I11d32c0a529ec76978cde38c038b4984ca13e8ba
Merge "Fix declaration of ForeignDBFile::delete()"