Use descriptive name for nobody

This matches the changes pushed to Fedora [1,2].

[1] https://fedoraproject.org/wiki/Changes/RenameNobodyUser
[2] https://pagure.io/setup/c/f6fdb5ffc87fc8f1acc211867fef4e3f0856edfc

src/nss-systemd/nss-systemd.c

@@ -46,7 +46,7 @@ static const struct passwd nobody_passwd = {
         .pw_passwd = (char*) PASSWORD_LOCKED_AND_INVALID,
         .pw_uid = UID_NOBODY,
         .pw_gid = GID_NOBODY,
-        .pw_gecos = (char*) "User Nobody",
+        .pw_gecos = (char*) "Kernel Overflow User",
         .pw_dir = (char*) "/",
         .pw_shell = (char*) NOLOGIN,
 };

sysusers.d/basic.conf.in

@@ -10,7 +10,7 @@ u root    0     "Super User" /root
 
 # The nobody user/group for NFS file systems
 g {{NOBODY_GROUP_NAME}} 65534       -            -
-u {{NOBODY_USER_NAME }} 65534:65534 "Nobody"     -
+u {{NOBODY_USER_NAME }} 65534:65534 "Kernel Overflow User"     -
 
 # Administrator group: can *see* more than normal users
 g adm     {{ADM_GID    }}     -            -