winealsa: Do not access WAVEHDR past DriverCallback.

dlls/winealsa.drv/wavein.c

diff --git a/dlls/winealsa.drv/wavein.c b/dlls/winealsa.drv/wavein.c
index d6337bc..625e36e 100644
--- a/dlls/winealsa.drv/wavein.c
+++ b/dlls/winealsa.drv/wavein.c
@@ -292,15 +292,15 @@
 		widRecorder_ReadHeaders(wwi);
 
 		/* return all buffers to the app */
-		for (lpWaveHdr = wwi->lpQueuePtr; lpWaveHdr; lpWaveHdr = lpWaveHdr->lpNext) {
+		while (wwi->lpQueuePtr) {
+		    lpWaveHdr = wwi->lpQueuePtr;
 		    TRACE("reset %p %p\n", lpWaveHdr, lpWaveHdr->lpNext);
+                    wwi->lpQueuePtr = lpWaveHdr->lpNext;
 		    lpWaveHdr->dwFlags &= ~WHDR_INQUEUE;
 		    lpWaveHdr->dwFlags |= WHDR_DONE;
-                    wwi->lpQueuePtr = lpWaveHdr->lpNext;
 		    widNotifyClient(wwi, WIM_DATA, (DWORD_PTR)lpWaveHdr, 0);
 		}
 
-		wwi->lpQueuePtr = NULL;
 		SetEvent(ev);
 		break;
 	    case WINE_WM_CLOSING: