Remove empty stub module Parser.pm from the distribution root

Older-style Perl distributions distribute their modules in the distribution
root instead of in a directory structure under lib/.  The existence of
Parser.pm and lib/Apache/Log/Parser.pm confuses some parts of the CPAN
ecosystem, such as MetaCPAN.  It finds the stub documentation in Parser.pm
instead of lib/Apache/Log/Parser.pm.
Merge pull request #2 from tsibley/remove-stub-module

Remove empty stub module Parser.pm from the distribution root