exec_close(): return -errno on errors (v2)

All qemu_fclose() callers were already changed to accept any negative
value as error, so we now can change it to return -errno.

When the process exits with a non-zero exit code, we return -EIO to as a
fake errno value.

Changes v1 -> v2:
 - Don't use "//" comments, to make checkpatch.pl happy
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

migration-exec.c

@@ -50,12 +50,9 @@ static int exec_close(MigrationState *s)
         ret = qemu_fclose(s->opaque);
         s->opaque = NULL;
         s->fd = -1;
-        if (ret >= 0 &&
-            WIFEXITED(ret)
-            && WEXITSTATUS(ret) == 0) {
-            ret = 0;
-        } else {
-            ret = -1;
+        if (ret >= 0 && !(WIFEXITED(ret) && WEXITSTATUS(ret) == 0)) {
+            /* close succeeded, but non-zero exit code: */
+            ret = -EIO; /* fake errno value */
         }
     }
     return ret;