On a clean 5.1 install if /var is a seperate partition anaconda creates an fstab
like: /dev/rootvg/varlogvol   /var/log                ext3    defaults,_netdev 1 2

This has the result of /var getting mounted much later in the boot sequence and
you get errors like the following:
Setting clock  (utc): Fri May  9 01:44:57 BST 2008 [  OK  ]
Starting udev: [  OK  ]
Setting hostname foobar.localhost:  [  OK  ]
Setting up Logical Volume Management:   7 logical volume(s) in volume group
"rootvg" now active [  OK  ]
Checking filesystems
Checking all file systems. [  OK  ]
Remounting root filesystem in read-write mode:  [  OK  ]
Mounting local filesystems:  [  OK  ]
Enabling local filesystem quotas:  [  OK  ]
touch: cannot touch `/var/lib/random-seed': No such file or directory
chmod: cannot access `/var/lib/random-seed': No such file or directory
/etc/rc.d/rc.sysinit: line 849: /var/run/utmp: No such file or directory
touch: cannot touch `/var/log/wtmp': No such file or directory
....
Starting NFS statd: statd: Could not chdir: No such file or directory [FAILED]
Starting system message bus: Could not create file /var/lib/dbus/machine-id: No
such file or directory
Failed to start message bus: Failed to bind socket
"/var/run/dbus/system_bus_socket": No such file or directory [FAILED]
....
Checking network-attached filesystems
...
/dev/rootvg/varvol: clean, 312/1048576 files, 108548/1048576 blocks
....

Bug #244994 is responsible for the change but it's not clear why the change was
introduced since the bug #238143 isn't visible.

It's been a while since I tried 5.0 but I am pretty sure that it worked fine
there so this is a regression.