* set -e: Abort on error.
* set -u: Emit error for undefined variables.
There was one case of unconditional access of a possibly
undefined variable in listRecentCommits.sh. Fixed by replacing
the old "x$x"="x" hack with an explicit emptiness check. The hack
is needed when supporting ancient non-bash shells, but this script
explicitly invokes a bash environment which 'test -z'.
Change-Id: I41a1c0d1bd57b5e241b83224096d32876fd913af