fetch: When aborting, ensure we note this to not multi-fail

When aborting a fetch, it may be cleaned up, in which case we
would otherwise send a spurious failure message too early. Instead
we record that the abort has occurred to suppress such an error.

Signed-off-by: Daniel Silverstone <dsilvers@digital-scurf.org>

content/fetch.c

@@ -585,6 +585,7 @@ fetch_start(nsurl *url,
 void fetch_abort(struct fetch *f)
 {
 	assert(f);
+	f->last_msg = FETCH__INTERNAL_ABORTED;
 	NSLOG(fetch, DEBUG,
 	      "fetch %p, fetcher %p, url '%s'", f, f->fetcher_handle,
 	     nsurl_access(f->url));

content/fetch.h

@@ -60,6 +60,12 @@ typedef enum {
  */
 #define FETCH_MIN_FINISHED_MSG FETCH_FINISHED
 
+/**
+ * This message is actually an internal message used to indicate
+ * that a fetch was aborted.  Do not send this, nor expect it.
+ */
+#define FETCH__INTERNAL_ABORTED FETCH_ERROR
+
 /**
  * Fetcher message data
  */