Fixed possible pointer error in libcapi

CHANGES

@@ -3,6 +3,7 @@ CHANGES
 
 HEAD
 ------------------
+- fixed possible pointer error in libcapi. receive-buffer is now cleared before using it.
 
 
 chan_capi-1.1.2

libcapi20/capi20.c

@@ -472,6 +472,8 @@ static unsigned char *get_buffer(unsigned applid, size_t *sizep, unsigned *handl
 	*sizep = ap->recvbuffersize;
 	*handle  = (buf->buf-ap->bufferstart)/ap->recvbuffersize;
 
+	memset(buf->buf, 0, ap->recvbuffersize);
+
 	return buf->buf;
 }