chrome-sdk: re-use existing PS1 for shell

Rather than create a custom PS1 that people aren't use to, try and
extract the value the user has set up already.  This should hopefully
provide a more familiar environment.

BUG=chromium:295110
TEST=`cros chrome-sdk` re-used my custom PS1

Change-Id: Ia3ba0abe8b55c45469ca956413470b26682e07a2
Reviewed-on: https://chromium-review.googlesource.com/289760
Reviewed-by: Michael Spang <spang@chromium.org>
Commit-Queue: Mike Frysinger <vapier@chromium.org>
Tested-by: Mike Frysinger <vapier@chromium.org>
1 file changed