third_party,jsonsign: bump openpgp to 188:61c59dda830a

http://camlistore.org/issue/370

Change-Id: I0066b1ad1455ff7960bda1f64ee953daa1195e1c
Merge "third_party,jsonsign: bump openpgp to 188:61c59dda830a"
Dockerfile: set bradfitz and /home/bradfitz

Change-Id: I3803af066cfdbae6d8ddc5790c1a6d37cf12be85