Fix .= initialization of attributes for types w/ :: in name

The Perl6::World needs all namespace parts as separate strings in the
Array, but currently it shoves the entire name as one item, which makes
World fail to find the needed type.

Fix by splitting the name on `::` before handing it to World.

Bug find: https://irclog.perlgeek.de/perl6/2017-01-23#i_13976744

src/Perl6/Actions.nqp

@@ -2895,7 +2895,9 @@ class Perl6::Actions is HLL::Actions does STDActions {
                             $initast, $*ATTR_INIT_BLOCK);
                     }
                     elsif $<initializer><sym> eq '.=' {
-                        my $type := $*W.find_symbol([ $*OFTYPE // 'Any']);
+                        my $type := $*W.find_symbol(
+                            nqp::split('::', $*OFTYPE // 'Any')
+                        );
                         my $dot_equals := $initast;
                         $dot_equals.unshift(QAST::WVal.new(:value($type)));
                         $dot_equals.returns($type);