plugins: fix return type of TCPSessGSSRecv()

The declaration and the implementation must use the same return type to
avoid an error -Werror=enum-int-mismatch.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

plugins/imgssapi/imgssapi.c

@@ -595,7 +595,7 @@ OnSessAcceptGSS(tcpsrv_t *pThis, tcps_sess_t *pSess)
 
 /* Replaces recv() for gssapi connections.
  */
-int TCPSessGSSRecv(tcps_sess_t *pSess, void *buf, size_t buf_len, ssize_t *piLenRcvd)
+rsRetVal TCPSessGSSRecv(tcps_sess_t *pSess, void *buf, size_t buf_len, ssize_t *piLenRcvd)
 {
 	DEFiRet;
 	gss_buffer_desc xmit_buf, msg_buf;