LU-13903 utils: have liblustreapi support Linux client

LU-13903 utils: have liblustreapi support Linux client

Handle two difference between the Linux client and the OpenSFS
branch. The Linux client doesn't support the LL_IOC_REMOVE_ENTRY
since its considered a security risk by the VFS maintainers. The
other difference is that struct getinfo_fid2path doesn't name its
union structure which is typical in the Linux kernel.

Test-Parameters: trivial
Change-Id: Ieb9ea749e8728f33621fd6ec28f78892466ec7a4
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/39207
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Wang Shilong <wshilong@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Olaf Faaland-LLNL <faaland1@llnl.gov>
Reviewed-by: Oleg Drokin <green@whamcloud.com>