Remove extraneous gitignore line.
The line for `#*` is a comment, but is not a useful one. It may
have been intended (and may be misread) to indicate temporary
files that start with `#`. Since no one has noticed for years that
it doesn't do that, I propose to remove the line. If someone finds
it appropriate to exclude files starting with a hash, they can add
a `\#*` line. If the line was a comment, then its meaning should
be explained in a separate change (potentially superceding this one).
Change-Id: Ice7f9b9bd11f3ac0360e567a744106a4a8ca1494