LU-6210 utils: Use C99 struct initializer for opt_map

LU-6210 utils: Use C99 struct initializer for opt_map

This patch makes no functional changes.  The opt_map struct
initializer in mount_lustre.c is updated to C99 syntax.

C89 positional initializers require values to be placed in the
correct order. This will cause errors if the fields of the struct
definition are reordered or fields are added or removed. C99 named
initializers avoid this problem, and also automatically clear any
values that are not explicitly set.

Test-Parameters: trivial
Signed-off-by: Steve Guminski <stephenx.guminski@intel.com>
Change-Id: I42532a6f6b3506e1893e137c054139f971241f61
Reviewed-on: https://review.whamcloud.com/27816
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>