Newer versions of R check suite now include running the checkbashisms
script, which highlights script constructs that are bash-like. Running
it locally highlighted a small thing (newline in echo, better to use
printf), while in CRAN it found an "unsafe" 'test -a' option, which was
always working anyways...

This commit "fixes" both problems, and will hopefully make CRAN happy
again.

Signed-off-by: Rodrigo Tobar <rtobar@icrar.org>