Fix version range so that Module::Install can understand.

lib/Module/Install/CPANfile.pm

@@ -17,13 +17,24 @@ sub cpanfile {
         while (my($type, $requirement) = each %$requirements) {
             if (my $command = $self->command_for($phase, $type)) {
                 while (my($mod, $ver) = each %$requirement) {
-                    $self->$command($mod, $ver);
+                    $self->$command($mod, $self->_fix_version($ver));
                 }
             }
         }
     }
 }
 
+sub _fix_version {
+    my($self, $ver) = @_;
+
+    return $ver unless $ver;
+
+    $ver =~ /(?:^|>=?)\s*([\d\.\_]+)/
+      and return $1;
+
+    $ver;
+}
+
 sub command_for {
     my($self, $phase, $type) = @_;