Updates atoms.proto for statsd.

Updates numbering for pulled atoms to start at 10,000 so we have more
room to add more pushed atoms. Also fixes definition for dropbox
error added to more efficiently encode -1, and include the package
name when it's available.

Test: Tested the dropbox atom is logged without crashing on marlin.
Change-Id: I096911e3fe134320f2b1c6f545b0f479c7199612