rados/rados.cc: init non-static members in default ctor

rados/rados.cc: init non-static members in default ctor

Fix for:

CID 717354 (#1 of 1): Uninitialized pointer field (UNINIT_CTOR)
 uninit_member: Non-static class member id is not initialized in
  this constructor nor in any functions that it calls.
 uninit_member: Non-static class member type is not initialized in
  this constructor nor in any functions that it calls.
 uninit_member: Non-static class member off is not initialized in
  this constructor nor in any functions that it calls.
 uninit_member: Non-static class member len is not initialized in
  this constructor nor in any functions that it calls.
 uninit_member: Non-static class member lg is not initialized in
  this constructor nor in any functions that it calls.
 uninit_member: Non-static class member completion is not
  initialized in this constructor nor in any functions that it calls.

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