Install appliance options

• PIAF_CANCEL : cancel appliance installation
• PIAF_FORCE : do not cancel installation and begin a new one
• if the previous installation became corrupted outside.
• PIAF_STOP : temporary stop appliance downloading

enum _PRL_INSTALL_APPLIANCE_FLAGS {
  PIAF_CANCEL = 1<<(PACF_MAX+1),
  PIAF_FORCE = 1<<(PACF_MAX+2),
  PIAF_STOP = 1<<(PACF_MAX+3)
};