Fix uninitialized use of length variable

Bad things must have been happening when this was hit.

This was introduced in commit 5cb4cd9d

src/switch_ivr_async.c

@@ -1132,6 +1132,9 @@ static switch_bool_t record_callback(switch_media_bug_t *bug, void *user_data, s
 			switch_time_t diff;
 			rh->wready = 1;
 			
+			nframe = switch_core_media_bug_get_native_write_frame(bug);
+			len = nframe->datalen;
+
 			if (!rh->rready) {
 				unsigned char fill_data[SWITCH_RECOMMENDED_BUFFER_SIZE] = {0};
 				switch_size_t fill_len = len;
@@ -1140,8 +1143,6 @@ static switch_bool_t record_callback(switch_media_bug_t *bug, void *user_data, s
 			}
 
 
-			nframe = switch_core_media_bug_get_native_write_frame(bug);
-			len = nframe->datalen;
 			
 
 			if (rh->last_write_time && rh->last_write_time < now) {