Update attribute parsing in site_host_attributes.

Host Labels in the database include values like board:x86-alex
and cros-version:x86-zgb-release/R22-2650.0.0.  This change updates
attribute parsing to recognize the embedded ':' as associating a
key (left of the ':') with a value (right of the ':').

BUG=None
TEST=ad hoc test using a private_host_attributes file

Change-Id: Ifa3b1e8d9c6efb2b18596b160ce819f89a453ebf
Reviewed-on: https://gerrit.chromium.org/gerrit/28992
Reviewed-by: Scott Zawalski <scottz@chromium.org>
Tested-by: Richard Barnette <jrbarnette@chromium.org>
Commit-Ready: Richard Barnette <jrbarnette@chromium.org>
1 file changed