minor variable init changes in init.cpp
minor variable init changes in init.cpp

- explicit init of pcoinsdbview and pwalletMain (even if not needed, as
  globals are init to NULL, it seems cleaner)
- remove check if (pwalletMain) in Shutdown() as delete is valid even if
  pwalletMain is NULL

Crowndev/crowncoin,Infernoman/crowncoin,domob1812/crowncoin,syscoin/syscoin,syscoin/syscoin,Crowndev/crowncoin,syscoin/syscoin,syscoin/syscoin,domob1812/crowncoin,domob1812/crowncoin,Infernoman/crowncoin,Infernoman/crowncoin,syscoin/syscoin,syscoin/syscoin,Crowndev/crowncoin,Infernoman/crowncoin,Crowndev/crowncoin,Infernoman/crowncoin,Infernoman/crowncoin,domob1812/crowncoin,Crowndev/crowncoin,Crowndev/crowncoin,syscoin/syscoin,syscoin/syscoin,domob1812/crowncoin,domob1812/crowncoin