For testing it is useful to be able to set the current directory used
for git operations, as well as the git-repo directory. Update some of
the functions to support this.

Signed-off-by: Simon Glass <sjg@chromium.org>

Add a helper to avoid needing to use a list within a list for this
simple case.

Update existing users of runpipe() to use this where possible.

Signed-off-by: Simon Glass <sjg@chromium.org>

This file has a lot of warnings. Before adding any more features, fix
those which are straightforward to resolve.

Signed-off-by: Simon Glass <sjg@chromium.org>

Throwing an Exception is not very friendly since it is the top-level
class of all exceptions. Declare a new class instead.

Signed-off-by: Simon Glass <sjg@chromium.org>

This should be in capitals and defined at the start of the file. Update
it.

Signed-off-by: Simon Glass <sjg@chromium.org>

It isn't clear why we need to have two different paths for closing down
the pipe. Unify them and use the Python to avoid this warning:

  subprocess.py:1127: ResourceWarning: subprocess 83531 is still running

Note that this code appears to originally have come from [1] and was
committed into the ChromeOS chromiumos/platform/crosutils repo in the
bin/cros_image_to_target.py file. The addition of the extra code path
came later, so that is chosen for the fixes tag.

[1] https://codereview.chromium.org/3391008

Signed-off-by: Simon Glass <sjg@chromium.org>
Fixes: a10fd93cbc patman: Make command methods return a CommandResult

The patman directory has a number of modules which are used by other tools
in U-Boot. This makes it hard to package the tools using pypi since the
common files must be copied along with the tool that uses them.

To address this, move these files into a new u_boot_pylib library. This
can be packaged separately and listed as a dependency of each tool.

Signed-off-by: Simon Glass <sjg@chromium.org>