Changes

pySim-shell: output git hash in case get_distribution fails

In case pySim-shell is used directly from the git repository (not
installed via a package manager), the version command fails with an
exception because pkg_resources.get_distribution('pySim') fails. In
that case, let's check if pySim-shell.py is inside a git repository
and if so, get the HEAD commit hash and display it instead.

Related: OS#6830
Change-Id: I2b9038f88cfcaa07894a2f09c7f5ad8a5474083d