(#15027, #15028, #15029) Fix upstart version parsing

A leading space in the --version argument would confuse upstart, and the
version returned would not always be a semantic version, which caused the
upstart provider to fail. This commit updates the initctl call to remove the
leading space from the --version argument, and also replaces the implicit
SemVer comparisons with wrapper functions that call out to
Puppet::Util::Package.versioncmp to do version comparisons. It also fixes a
subtly broken regex to grab the full version string.