Windows queries the default ccache name via the registry. Prior
to this change only the HKEY_CURRENT_USER hive. Fallback to
HKEY_LOCAL_MACHINE if there is no "ccname" value specified for the
user. This permits system or domain administrators to set the
default ccache to MSLSA: for all users.
Change-Id: Ide3b51358f8fc6944ca698e4a68295be9463d4e0