ext2: Initialize i_flag after allocation.

We use i_flag to carry some flags like IN_E4INDEX which newer
ext2fs variants uses internally.

fsck.ext3 rightfully complains after our implementation tags
non-directory inodes with INDEX_FL.

Initializing i_flag during allocation removes the noise factor
and quiets down fsck.

Patch from: Damjan Jovanovic
PR: 206530