Elytron filesystem-realm should load existing identities from file system

[standalone@localhost:9990 /] /subsystem=elytron/filesystem-realm=realm/identity=user:read-identity
{
    "outcome" => "failed",
    "failure-description" => "WFLYCTL0216: Management resource '[
    (\"subsystem\" => \"elytron\"),
    (\"filesystem-realm\" => \"realm\"),
    (\"identity\" => \"user\")
]' not found",
    "rolled-back" => true
}
[standalone@localhost:9990 /] /subsystem=elytron/filesystem-realm=realm/identity=user:add
{
    "outcome" => "failed",
    "failure-description" => "WFLYELY01000: Identity with name [user] already exists.",
    "rolled-back" => true
}