This fixes one Eclipse "no valid properties files exist in the
localization directory specified" warning.
Ordinarily I would also change this project's configuration to treat
this warning as an error in the future. That's a good way to
discourage regressions. Unfortunately in this particular case I
cannot find a setting that has the desired effect, even after hunting
around in Eclipse PDE sources. It seemed that setting
"compilers.p.unknown-resource=0" in
"com.ibm.wala.util/.settings/org.eclipse.pde.prefs" should do the
trick, but it does not. I don't know why.