convert ext4 to ->evict_inode()

pretty much brute-force...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --cc fs/ext4/ext4.h
Simple merge

diff --cc fs/ext4/ialloc.c
Simple merge

diff --cc fs/ext4/inode.c
Simple merge

diff --cc fs/ext4/super.c
Simple merge