ipfixprobe:tests: MSS fix

Author: hulakmat

tests/functional/reference/basicplus

@@ -7,4 +7,4 @@
 54.175.222.246,192.168.0.30,130,459,0,258,258,2016-04-07T18:23:32.300116,2016-04-07T18:23:32.535279,78:44:76:36:98:19,dc:53:60:2b:6a:4c,1,1,0,0,80,44586,0,229,280,0,2,2,64,41,6,24,24
 54.175.222.246,192.168.0.30,138,0,0,258,0,2016-04-07T18:23:31.598243,2016-04-07T18:23:31.598243,78:44:76:36:98:19,dc:53:60:2b:6a:4c,1,0,0,0,80,44582,0,229,0,0,2,0,64,0,6,24,0
 54.175.222.246,192.168.0.30,200,36844,0,258,258,2016-04-07T18:23:33.713573,2016-04-07T18:23:34.034665,78:44:76:36:98:19,dc:53:60:2b:6a:4c,1,20,0,0,80,44594,0,229,279,0,2,2,64,41,6,24,24
-ipaddr DST_IP,ipaddr SRC_IP,uint64 BYTES,uint64 BYTES_REV,uint64 LINK_BIT_FIELD,uint64 TCP_OPT,uint64 TCP_OPT_REV,time TIME_FIRST,time TIME_LAST,macaddr DST_MAC,macaddr SRC_MAC,uint32 PACKETS,uint32 PACKETS_REV,uint32 TCP_MSS,uint32 TCP_MSS_REV,uint16 DST_PORT,uint16 SRC_PORT,uint16 TCP_SYN_SIZE,uint16 TCP_WIN,uint16 TCP_WIN_REV,uint8 DIR_BIT_FIELD,uint8 IP_FLG,uint8 IP_FLG_REV,uint8 IP_TTL,uint8 IP_TTL_REV,uint8 PROTOCOL,uint8 TCP_FLAGS,uint8 TCP_FLAGS_REV
+ipaddr DST_IP,ipaddr SRC_IP,uint64 BYTES,uint64 BYTES_REV,uint64 LINK_BIT_FIELD,uint64 TCP_OPT,uint64 TCP_OPT_REV,time TIME_FIRST,time TIME_LAST,macaddr DST_MAC,macaddr SRC_MAC,uint32 PACKETS,uint32 PACKETS_REV,uint16 TCP_MSS,uint16 TCP_MSS_REV,uint16 DST_PORT,uint16 SRC_PORT,uint16 TCP_SYN_SIZE,uint16 TCP_WIN,uint16 TCP_WIN_REV,uint8 DIR_BIT_FIELD,uint8 IP_FLG,uint8 IP_FLG_REV,uint8 IP_TTL,uint8 IP_TTL_REV,uint8 PROTOCOL,uint8 TCP_FLAGS,uint8 TCP_FLAGS_REV