Picago was very old and had local changes, update to latest release.
Also update to latest oauth2 as a transitive dependency.
Actual versions:
github.com/tgulacsi/picago: 9e1ac2306c701ca7477a169b2b49902b7b4c58bf
golang.org/x/oauth2: 197281d4e0ecd78c33865daf9c6e51626feefcb2
manually omit oauth2 testdata and tests that contain private keys to
make "devcam review" happy
This change was prepared using the forthcoming migration to the dep
tool.
Manually tested by setting up a new Picasa oauth config and importing
many photos.
Addresses: #889
Change-Id: I4d21941ccb4ade84ec658b5cfc8624e29f52be60
Paul Lindner