helpcompiler: avoid -Werror=deprecated-copy (GCC trunk towards GCC 9)

...by removing explicitly user-provided functions that do the same as their
implicitly-defined counterparts, but may prevent implicitly declared copy
functions from being defined as non-deleted in the future

Change-Id: I61182be57a0ed9071e3559a6445aee98ec5c19bf
Reviewed-on: https://gerrit.libreoffice.org/58057
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

helpcompiler/inc/HelpCompiler.hxx

@@ -65,7 +65,6 @@ namespace fs
         OUString data;
     public:
         path() {}
-        path(const path &rOther) : data(rOther.data) {}
         path(const std::string &in, convert)
         {
             OUString sWorkingDir;