Raw Constructors that accept arrays/hashes as params should not process empty structures

[dayglojesus]

If a Raw Constructor class is declared and its params specify an empty data structure, the class should not prepare resources.

Example:

include managedmac::groups
# Create an empty Hash
$accounts = {}
class { 'managedmac::groups':
  accounts => $accounts,
}

This code will result in an error.