LU-12355 ldiskfs: Added ext4_iget_flags to ext4_iget

LU-12355 ldiskfs: Added ext4_iget_flags to ext4_iget

Kernel 4.19 introduced ext4_iget_flags and changed ext4_iget
to require a flags argument.

Use EXT4_IGET_HANDLE for stale inode checking by ext4/ldiskfs

Linux-commit: 8a363970d1dc38c4ec4ad575c862f776f468d057

Test-Parameters: trivial
Change-Id: Ic6cbe3eabcdbb1a506813d145fb2980dbed95e66
Signed-off-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-on: https://review.whamcloud.com/35023
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>