After the regression introduced by [1] the Gerrit static
documentation was not available anymore in the standard Jetty embedded
server scenario. This change is the ideal completion of the refactoring
of the Jetty-controlled static resources serving legacy logic into
the new Gerrit-driven ResourceServlet mechanism.
[1] https://gerrit-review.googlesource.com/#/c/72085/
Change-Id: I554adc51766554e5dde039fc83d2d480525ab7af
7ec8bb3f60