Omnibus package uses chcon rather than fcontext for SElinux contexts

chcon is transitive, running restorecon will wipe all 'custom' contexts.

The Omnibus package should add the contexts proper using i.e. semanage fcontext

Supplemental case to this issue: If one uses a nonstandard mountpoint (such as NFS or FUSE) for certain locations, the gitlab-ctl reconfigure chef cookbook will error out due to its inability to force those locations to the SELinux context it believes that location should be. By way of example:

[root@gitlab-node2 gitlab]# pwd ; ls -laZ /var/opt/gitlab drwxr-xr-x. root root unconfined_u:object_r:var_t:s0 . drwxr-xr-x. root root system_u:object_r:var_t:s0 .. drwx------. git root unconfined_u:object_r:var_t:s0 backups -rw-------. root root unconfined_u:object_r:var_t:s0 bootstrapped -rw-r--r--. git git unconfined_u:object_r:var_t:s0 .gitconfig drwx------. git git system_u:object_r:fusefs_t:s0 git-data drwxr-xr-x. git gitlab-www system_u:object_r:fusefs_t:s0 gitlab-ci drwxr-x---. git gitlab-www unconfined_u:object_r:var_t:s0 gitlab-git-http-server drwxr-xr-x. git gitlab-www unconfined_u:object_r:var_t:s0 gitlab-rails drwx------. git git system_u:object_r:fusefs_t:s0 gitlab-shell drwxr-x---. git gitlab-www unconfined_u:object_r:var_t:s0 gitlab-workhorse drwx------. root root unconfined_u:object_r:var_t:s0 logrotate drwxr-x---. root gitlab-www unconfined_u:object_r:var_t:s0 nginx drwxr-xr-x. gitlab-psql root unconfined_u:object_r:var_t:s0 postgresql drwxr-x---. gitlab-redis git unconfined_u:object_r:var_t:s0 redis drwx------. git git system_u:object_r:fusefs_t:s0 .ssh -rw-------. git git unconfined_u:object_r:var_t:s0 .viminfo

Moved from gitlab-org/gitlab-ce#13504

mentioned in issue #1106