I noticed this in my log file...

[2015-05-21 18:10:02 CDT] main: starting assistant version 5.20150508-gf71c23f
(started...) gpg: keyring `/Applications/git-annex.app/Contents/MacOS/trustedkeys.gpg' created
...
[2015-05-21 18:10:02 CDT] Upgrader: Checking if an upgrade is available.
...
[2015-05-21 18:10:02 CDT] call: curl ["-s","-f","-L","-C","-","-#","-o","/var/folders/zk/tk15c40n6h1bjl94ntk5md8h0000gn/T/git-annex.tmp.0/info.sig","http://downloads.kitenet.net/git-annex/OSX/current/10.10_Yosemite/git-annex.dmg.info.sig","--user-agent","git-annex/5.20150419-g900e1b6"]
[2015-05-21 18:10:03 CDT] call: gpg ["--no-default-keyring","--no-auto-check-trustdb","--no-options","--homedir","/var/folders/zk/tk15c40n6h1bjl94ntk5md8h0000gn/T/git-annex-gpg.tmp.0","--keyring","/Applications/git-annex.app/Contents/MacOS/trustedkeys.gpg","--verify","/var/folders/zk/tk15c40n6h1bjl94ntk5md8h0000gn/T/git-annex.tmp.0/info.sig"]
gpg: Signature made Fri May  8 15:10:28 2015 CDT using DSA key ID 89C809CB
gpg: Can't check signature: public key not found
[2015-05-21 18:10:03 CDT] Upgrader: Failed to check if upgrade is available.

So I copied trustedkeys.gpg from the bundle folder to the MacOS folder, replacing the newly created trustedkeys.gpg and now I get this... which is better...

[2015-05-21 18:17:24 CDT] main: starting assistant version 5.20150508-gf71c23f
...
[2015-05-21 18:17:25 CDT] Upgrader: Checking if an upgrade is available.
...
[2015-05-21 18:17:25 CDT] call: curl ["-s","-f","-L","-C","-","-#","-o","/var/folders/zk/tk15c40n6h1bjl94ntk5md8h0000gn/T/git-annex.tmp.0/info","http://downloads.kitenet.net/git-annex/OSX/current/10.10_Yosemite/git-annex.dmg.info","--user-agent","git-annex/5.20150508-gf71c23f"]
...
[2015-05-21 18:17:25 CDT] call: curl ["-s","-f","-L","-C","-","-#","-o","/var/folders/zk/tk15c40n6h1bjl94ntk5md8h0000gn/T/git-annex.tmp.0/info.sig","http://downloads.kitenet.net/git-annex/OSX/current/10.10_Yosemite/git-annex.dmg.info.sig","--user-agent","git-annex/5.20150508-gf71c23f"]
[2015-05-21 18:17:25 CDT] call: gpg ["--no-default-keyring","--no-auto-check-trustdb","--no-options","--homedir","/var/folders/zk/tk15c40n6h1bjl94ntk5md8h0000gn/T/git-annex-gpg.tmp.0","--keyring","/Applications/git-annex.app/Contents/MacOS/trustedkeys.gpg","--verify","/var/folders/zk/tk15c40n6h1bjl94ntk5md8h0000gn/T/git-annex.tmp.0/info.sig"]
gpg: Signature made Fri May  8 15:10:28 2015 CDT using DSA key ID 89C809CB
gpg: /var/folders/zk/tk15c40n6h1bjl94ntk5md8h0000gn/T/git-annex-gpg.tmp.0/trustdb.gpg: trustdb created
gpg: Good signature from "git-annex distribution signing key (for Joey Hess) "
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: 4005 5C6A FD2D 526B 2961  E78F 5EE1 DBA7 89C8 09CB
[2015-05-21 18:17:25 CDT] Upgrader: No new version found.

FYI