Fixed fs_mgr#fs_mgr_read_fstab_file_proc_mounts test

It was failing with:
Expected equality of these values:
mnt_opts
Which is: { "data=ordered", "discard", "noatime", "nodev", "nosuid", "rw", "seclabel", "sync" }
fs_options
Which is: { "data=ordered", "discard", "noatime", "nodev", "nosuid", "rw", "seclabel" }

Test: atest fs_mgr_unit_test
Change-Id: I3bb084d62e81fda8948a100515bdaad62d18bb54