fixed issue with $c in print_response

Author: srchulo

lib/jQuery/File/Upload.pm

@@ -656,13 +656,13 @@ sub is_image { shift->{is_image} }
 sub print_response { 
 	my $self = shift;
 
-	#thanks to Lukas Rampa for this suggestion
-	my $content_type = 'text/plain';
-  if ($c->req->headers->header('Accept') =~ qr(application/json) ) {
-	  $content_type = 'application/json';
-  }
-
 	if(defined $self->ctx) { 
+
+		#thanks to Lukas Rampa for this suggestion
+  		if ($self->ctx->req->headers->header('Accept') =~ qr(application/json) ) {
+	  		$content_type = 'application/json';
+  		}
+
 		$self->ctx->stash->{current_view} = '';
 		$self->ctx->res->content_type("$content_type; charset=utf-8");
 		$self->ctx->res->body($self->output . ""); #concatenate "" for when there is no output