Fix error message on ifquery when sysctl bridge-stp-user-space

Fix error message on ifquery when sysctl bridge-stp-user-space

This fix this kind of error:

error: bond0: cmd '/sbin/sysctl net.bridge.bridge-stp-user-space' failed: returned 255 (sysctl: cannot stat /proc/sys/net/bridge/bridge-stp-user-space: No such file or directory
)
error: fwpr103p0: cmd '/sbin/sysctl net.bridge.bridge-stp-user-space' failed: returned 255 (sysctl: cannot stat /proc/sys/net/bridge/bridge-stp-user-space: No such file or directory
)