system: replace nogroup with nobody

Currently, we define the so-called "overflow group" as 'nogroup'.

However, one practical issue is that systemd-sysusers will otherwise
create a 'nobody' group with gid 999, because that's is what is usual to
define the overflow group: users and groups are defined in LSB (Linux
Standard Base):

    https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/usernames.html

Quoting: "If the username exists on a system,then they should be in the
suggested corresponding group".

Only Debian and derivatives depart from this custom, naming it 'nogroup'
(hence the rationale for commit 908198e756 (system/skeleton: remove
spurious group 'nobody').

See also commit 9c67af2c52 (system/skeleton: use uid/gid 65534 for
nobody/nogroup), and a related discussion on LWN.net (key is "overflow
UID" which also applies to GID):

    https://lwn.net/Articles/695478/

Use the recommended groupname 'nobody'. Adapt packages accordingly.

Signed-off-by: Norbert Lange <nolange79@gmail.com>
[yann.morin.1998@free.fr:
  - reword commit log
  - extend commit log with more references (commits and LWN)
]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

package/boa/boa.conf

@@ -46,7 +46,7 @@ Port 80
 # Group: The group name or GID the server should run as.
 
 User nobody
-Group nogroup
+Group nobody
 
 # ServerAdmin: The email address where server problems should be sent.
 # Note: this is not currently used, except as an environment variable

package/mosquitto/mosquitto.mk

@@ -114,7 +114,7 @@ define MOSQUITTO_INSTALL_INIT_SYSTEMD
 endef
 
 define MOSQUITTO_USERS
-	mosquitto -1 nogroup -1 * - - - Mosquitto user
+	mosquitto -1 nobody -1 * - - - Mosquitto user
 endef
 endif
 

package/oracle-mysql/oracle-mysql.mk

@@ -102,7 +102,7 @@ ORACLE_MYSQL_CONF_OPTS += --without-debug
 endif
 
 define ORACLE_MYSQL_USERS
-	mysql -1 nogroup -1 * /var/mysql - - MySQL daemon
+	mysql -1 nobody -1 * /var/mysql - - MySQL daemon
 endef
 
 define ORACLE_MYSQL_ADD_FOLDER

package/systemd/systemd.mk

@@ -38,7 +38,6 @@ SYSTEMD_CONF_OPTS += \
 	-Dsulogin-path=/usr/sbin/sulogin \
 	-Dmount-path=/usr/bin/mount \
 	-Dumount-path=/usr/bin/umount \
-	-Dnobody-group=nogroup \
 	-Didn=true \
 	-Dnss-systemd=true
 

system/skeleton/etc/group

@@ -23,4 +23,4 @@ staff:x:50:
 lock:x:54:
 netdev:x:82:
 users:x:100:
-nogroup:x:65534:
+nobody:x:65534: