criu(8): Move --log-pid under restore

The --log-pid option was introduced with commit

fc7bedc50a
crtools: make to be able to split messages by pid

This option is applicable only for restore. Therefore, move the
documentation from "Common options" to "restore".

Signed-off-by: Radostin Stoyanov <rstoyanov1@gmail.com>
Signed-off-by: Andrei Vagin <avagin@gmail.com>

Documentation/criu.txt

@@ -65,9 +65,6 @@ The following levels are available:
 *-o*, *--log-file* 'file'::
     Write logging messages to 'file'.
 
-*--log-pid*::
-    Write separate logging files per each pid.
-
 *--display-stats*::
     During dump as well as during restore *criu* collects information
     like the time required to dump or restore the process or the
@@ -373,6 +370,9 @@ usually need to be escaped from shell.
     Restore root task as a sibling (makes sense only with
     *--restore-detached*).
 
+*--log-pid*::
+    Write separate logging files per each pid.
+
 *-r*, *--root* 'path'::
     Change the root filesystem to 'path' (when run in a mount namespace).