static-id: add missing netdata group

The netdata recipe does want to create a netdata group. So add it to the
static id for the reproducibility tests.

Signed-off-by: Yoann Congal <yoann.congal@smile.fr>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

meta-webserver/files/static-group-meta-webserver

@@ -0,0 +1 @@
+netdata:x:691

meta-webserver/files/static-passwd-meta-webserver

@@ -1,2 +1,2 @@
 www:x:690:nogroup::/:/bin/nologin
-netdata:x:691:nogroup::/:/bin/nologin
+netdata:x:691:691::/:/bin/nologin