staging/lustre/lfsck: LFSCK 1.5 technical debts (3)

Original patch resolves some LFSCK 1.5 technical debts, including:
1) Check and remove repeated linkea entries.
2) Merge some "goto" branches to make the code more readable.
3) Some comments about object's nlink inconsistency processing.

This patch picks the obd flags change.

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2915
Lustre-change: http://review.whamcloud.com/6344Signed-off-by: NFan Yong <fan.yong@intel.com>
Reviewed-by: NAlex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: NAndreas Dilger <andreas.dilger@intel.com>
Reviewed-by: NOleg Drokin <oleg.drokin@intel.com>
Signed-off-by: NPeng Tao <tao.peng@emc.com>
Signed-off-by: NAndreas Dilger <andreas.dilger@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/include/obd_support.h

@@ -470,6 +470,7 @@ int obd_alloc_fail(const void *ptr, const char *name, const char *type,
 #define OBD_FAIL_LFSCK_DELAY3		0x1602
 #define OBD_FAIL_LFSCK_LINKEA_CRASH	0x1603
 #define OBD_FAIL_LFSCK_LINKEA_MORE	0x1604
+#define OBD_FAIL_LFSCK_LINKEA_MORE2	0x1605
 #define OBD_FAIL_LFSCK_FATAL1		0x1608
 #define OBD_FAIL_LFSCK_FATAL2		0x1609
 #define OBD_FAIL_LFSCK_CRASH		0x160a