fixes: skip if the vstring has no magic

which happens in <5.8.1, tested with 5.6

expected to be squashed

Author: tonycoz

dist/Devel-PPPort/parts/inc/magic

@@ -628,7 +628,7 @@ SvVSTRING(sv)
     OUTPUT:
         RETVAL
 
-=tests plan => 65
+=tests plan => 64
 
 # Find proper magic
 ok(my $obj1 = Devel::PPPort->new_with_mg());
@@ -776,9 +776,12 @@ is tied($big)->{store}, 0;
 SKIP:
 {
     my $vstr = eval "v1.23.456";
-    $vstr
-        or skip "No vstrings", 2;
-    ok Devel::PPPort::SvVOK($vstr), '$vstr has SvVOK';
+
+    if (!Devel::PPPort::SvVOK($vstr)) {
+        skip "No vstring magic", 1;
+        last SKIP; # testutil skip() doesn't "last SKIP"
+    }
+
     is Devel::PPPort::SvVSTRING($vstr), "v1.23.456", 'SvVSTRING()';
 }