bash-completion: Future-proof --help-*-list "cXXXX version" filtering

A future version of CMake may not print the "cmake version" line at the
beginning of the --help-*-list output.  Filter out the line with 'grep'
instead of 'tail' to tolerate output from versions of CMake with and
without the version line.  Match "cmake version", "cpack version", and
"ctest version" in each corresponding completion script.
Merge topic 'bash-completion-future-filter'

a8d7141 bash-completion: Future-proof --help-*-list "cXXXX version" filtering