Fix the following -Werror warning from clang 10.0.0 in procstat:

usr.bin/procstat/procstat_sigs.c:79:3: error: misleading indentation; statement is not part of the previous 'else' [-Werror,-Wmisleading-indentation]

xo_close_container(name);
^

usr.bin/procstat/procstat_sigs.c:77:4: note: previous statement is here

} else
  ^

The intent was to group the xo_close_container() call to the previous
snprintf() call.

MFC after: 3 days