Teach Git to resolve the executable directory before initializing
Trace2. This allows the system configuration directory to be
discovered earlier (because it is sometimes relative to the prefix
or runtime-prefix).
This will be used by the next commit to allow trace2 settings to
be loaded from the system config.
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>