Remove empty package test and validation

an empty variable is apparently the same thing as undef, which causes
the packages to be selected as usual.

manifests/init.pp

@@ -47,9 +47,6 @@ class java(
   include java::params
 
   validate_re($version, 'present|installed|latest|^[.+_0-9a-zA-Z:-]+$')
-  if $package != undef {
-    validate_slength($package,255,1)
-  }
 
   if has_key($java::params::java, $distribution) {
     $default_package_name     = $java::params::java[$distribution]['package']