Prevent an empty line in /proc/self/status, allow iotop to work.

iotop does not like empty lines, fails with:
  File "/usr/local/lib64/python2.7/site-packages/iotop/data.py", line
196, in parse_proc_pid_status
    key, value = line.split(':\t', 1)
ValueError: need more than 1 value to unpack

[reading /proc/self/status]

Fixes: 84964fa3e5a0 ("proc: Provide details on speculation flaw mitigations")
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>