Update jgarzik email, PGP public key block.

[jgarzik]

PGP cross-validation:
http://gtf.org/garzik/bitcoin/psa3-bitpay.txt
http://gtf.org/garzik/bitcoin/psa3-pobox.txt

[laanwj]

ACK, matches the key that I have

[harding]

ACK jgarzik/bitcoin.org@19d26b8. Verified that http://gtf.org/garzik/bitcoin/psa3-bitpay.txt is signed by the jgarzik-bitpay.asc key currently in the repository and that it lists the key ID of the key being added in this PR.

@jgarzik two questions:

1. Can you clean up the key block being added in this request? It has a bunch of revoked/expired keys in it:

   phobos:148:~/dev/bitcoin.org$ gpg jgarzik-pobox.asc 
   pub  1024D/03CC8A77 2005-05-27 [revoked]
   uid                            Jeff Garzik <jgarzik@pobox.com>
   sub  2048g/CB9C16DB 2005-05-27 [revoked: 2009-11-07]
   pub  1024D/707FFFD2 2009-11-07 [revoked]
   uid                            Jeff Garzik <jgarzik@pobox.com>
   sub  4096g/68998285 2009-11-07 [revoked: 2011-10-18]
   pub  4096R/01782B2F 2011-10-17 Jeff Garzik <jgarzik@pobox.com>
   sub  4096R/2AA9AC3A 2011-10-17 [expires: 2017-10-15]
   

2. Do we still need the jgarzik-exmulti.asc file in the repository? If not, can you also remove it in this PR?

[jgarzik]

@harding

1. It's the standard "gpg --armor --export" output, higher security to have revoked keys in there, and it's very little data overall.

2. sure

[harding]

ACK 704aa21 -- verified it has the same key I verified above. @jgarzik thanks for updating!

In the absence of critical feedback, this pull will be merged on Wednesday.

[saivann]

Perhaps late, but I confirm that I just verified the chain of trust between previous and new keys.