LU-11264 llapi: clean up llapi_file_create_foreign()

LU-11264 llapi: clean up llapi_file_create_foreign()

Clean up the error handling in llapi_file_create_foreign() to always
set errno, and avoid printing a duplicate error message when run on
a non-Lustre filesystem.

Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I610748f5d07566fb81c2f0b6f59507e97e03158f
Reviewed-on: https://review.whamcloud.com/35093
Reviewed-by: Faccini Bruno <bruno.faccini@intel.com>
Reviewed-by: Olaf Faaland-LLNL <faaland1@llnl.gov>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>