generators: drop umask calls

systemd already sets the umask (see e3b8d0637d). When
running under systemd, we don't need to set it. And when *not* running under
systemd, for example during development, there is no reason to override the user
config. Let's just drop those calls.

$ git grep -e 'umask\(' -l 'src/*generator*' |xargs perl -i -0pe 's|^[^\n]*umask\([^\n]+\n\n||gms'

src/debug-generator/debug-generator.c

@@ -155,8 +155,6 @@ static int run(int argc, char *argv[]) {
 
         log_setup_generator();
 
-        umask(0022);
-
         r = proc_cmdline_parse(parse_proc_cmdline_item, NULL, PROC_CMDLINE_RD_STRICT | PROC_CMDLINE_STRIP_RD_PREFIX);
         if (r < 0)
                 log_warning_errno(r, "Failed to parse kernel command line, ignoring: %m");