Fix port range schema in shell-manager util module
Fix port range schema in shell-manager util module

The voluptuous "port_range_schema" in shell_manager.util allowed ports
up to 66635. But a port ranges from 0 to 65535.

picoCTF/picoCTF,picoCTF/picoCTF,royragsdale/picoCTF,picoCTF/picoCTF,royragsdale/picoCTF,picoCTF/picoCTF,picoCTF/picoCTF,picoCTF/picoCTF,royragsdale/picoCTF,royragsdale/picoCTF,royragsdale/picoCTF,royragsdale/picoCTF,royragsdale/picoCTF