[libfsimage/zfs] compilation fix ZFS libfsimage support.

Depending on environments, zfs libfsimage support doesn't compile.
This patch fixes it.

ia64-linux-gnu-gcc -DPIC -O2 -fomit-frame-pointer
-fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes
-Wno-unused-value -Wdeclaration-after-statement
-I/usr/ia64-linux-gnu/
sys-root/usr/include -D__XEN_TOOLS__ -D_LARGEFILE_SOURCE
-D_LARGEFILE64_SOURCE -I../../../tools/libfsimage/common/ -Werror
-Wp,-MD,.zfs_lzjb.opic.d -fPIC -c -o zfs_lzjb.opic zfs_
lzjb.c
In file included from fsys_zfs.h:41,
from zfs_lzjb.c:25:
zfs-include/zfs_acl.h:29: error: redefinition of typedef uid_t
/usr/ia64-linux-gnu/sys-root/usr/include/sys/types.h:82: error:
previous declaration of uid_t was here

This depends on how __uid_t is defined in the system header.
No file under the zfs directory uses uid_t so that just removing
the definition in the zfs_acl.h looks reasonable.

Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>

     1.1 --- a/tools/libfsimage/zfs/zfs-include/zfs_acl.h	Fri May 02 13:46:16 2008 +0100
     1.2 +++ b/tools/libfsimage/zfs/zfs-include/zfs_acl.h	Fri May 02 13:47:01 2008 +0100
     1.3 @@ -24,11 +24,6 @@
     1.4  #ifndef	_SYS_FS_ZFS_ACL_H
     1.5  #define	_SYS_FS_ZFS_ACL_H
     1.6  
     1.7 -#ifndef _UID_T
     1.8 -#define	_UID_T
     1.9 -typedef	unsigned int uid_t;			/* UID type */
    1.10 -#endif /* _UID_T */
    1.11 -
    1.12  typedef struct zfs_oldace {
    1.13  	uint32_t	z_fuid;		/* "who" */
    1.14  	uint32_t	z_access_mask;  /* access mask */