(MODULES-910) Convert @apache_version to a string

Three part version numbers cannot be floats and must
be represented as strings. This commit changes all instances
of $apache_version and any comparsions to use strings and the
versioncmp function.

This also fixes comparsion of Float and String errors with future
parser enabled.
Merge pull request #731 from blkperl/convert_versions_to_string

(MODULES-910) Convert @apache_version to a string
Merge branch 'master' of https://github.com/puppetlabs/puppetlabs-apache