rgw_rest_log.h: remove http_ret from some RGWOp_*_list classes

rgw_rest_log.h: remove http_ret from some RGWOp_*_list classes

Remove http_ret from child class since there is already an integer
with the same name in the parent/base class.

Fix for:

[src/rgw/rgw_rest_log.h:79] -> [src/rgw/rgw_rest.h:275]: (warning) The
 class 'RGWOp_MDLog_List' defines member variable with name 'http_ret'
 also defined in its parent class 'RGWRESTOp'.
[src/rgw/rgw_rest_log.h:99] -> [src/rgw/rgw_rest.h:275]: (warning) The
 class 'RGWOp_MDLog_Info' defines member variable with name 'http_ret'
 also defined in its parent class 'RGWRESTOp'.
[src/rgw/rgw_rest_log.h:182] -> [src/rgw/rgw_rest.h:275]: (warning) The
 class 'RGWOp_DATALog_List' defines member variable with name 'http_ret'
 also defined in its parent class 'RGWRESTOp'.
[src/rgw/rgw_rest_log.h:202] -> [src/rgw/rgw_rest.h:275]: (warning) The
 class 'RGWOp_DATALog_Info' defines member variable with name 'http_ret'
 also defined in its parent class 'RGWRESTOp'.

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>