when its wholeref index lines contain any "sha1-" wholeref lines.
Then, have the client use that info when uploading files to also
compute the sha-1 (in addition to the sha-224) and ask the server for
both.
By client, we mean changes to cmd/camput, to pkg/client functions (for
camput and other Go clients, such as the apps), and to the web UI.
Also, add a -sha1 mode to devcam server, as well as the
CAMLI_SHA1_ENABLED env var, to facilitate testing/debugging of the
legacy sha1 mode. Fix/document unrelated options in devcam server
while we're at it.
Change-Id: I369679d2a4719f6f8b409f78dd4d065e13a3f62f