Revert "Add old ruby support to inet6_prefix"

This reverts commit efffd27a41.

Reason for revert:
The logic was added to support ruby 1.x.x which does not contain [1],
but recent operating systems no longer ship such an old version.

CentOS 9: Ruby 3.0
CentOS 8: Ruby 2.5
Ubuntu 20.04: Ruby 2.7

[1] e03d266c1d

Change-Id: I7c633f8d12e4678910872b7782273b2ca2c76d65

lib/puppet/functions/inet6_prefix.rb

@@ -8,15 +8,6 @@ Puppet::Functions.create_function(:inet6_prefix) do
   def inet6_prefix(*args)
     require 'ipaddr'
 
-    # NOTE(tobias-urdin): Add support for older version of the ipaddr
-    # lib where ArgumentError hasn't been replaced yet.
-    if IPAddr.const_defined?('InvalidAddressError')
-      exp = [IPAddr::AddressFamilyError, IPAddr::Error, IPAddr::InvalidAddressError,
-             IPAddr::InvalidPrefixError, ArgumentError, NoMethodError]
-    else
-      exp = [ArgumentError, NoMethodError]
-    end
-
     result = []
     args = args[0] if args[0].kind_of?(Array)
     args = [args] unless args.kind_of?(Array)
@@ -29,7 +20,7 @@ Puppet::Functions.create_function(:inet6_prefix) do
             ip = "inet6:[#{ip_parts.shift}]#{ip_parts.join}"
           end
         end
-      rescue *exp
+      rescue IPAddr::AddressFamilyError, IPAddr::Error, IPAddr::InvalidAddressError, IPAddr::InvalidPrefixError, ArgumentError, NoMethodError => e
         # ignore it
       end
       result << ip