MODULES-1446: mod_version is now builtin

while we are not loading it (by default), we should make it easier for
people transitioning their configuration from 2.2 to 2.4 to find issues:
thus adding a warning when someone tries to load mod_version.

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things i have learned during this pr:

× @hunner: There is no '&&' in puppet; only 'and'*

× add puppet to PATH, so vim can check syntax. thanks @mhaskel
especially for the patience.

*zuhl.