Drop unused init.h includes

These were entirely unused, as based on successful compilation
and a grep for:
  \bStartShutdown\(\)|\bShutdownRequested\(\)|\bInterrupt\(\)|\bShutdown\(\)|\bInitLogging\(\)|\bInitParameterInteraction\(\)|\bAppInitBasicSetup\(\)|\bAppInitParameterInteraction\(\)|\bAppInitSanityChecks\(\)|\bAppInitLockDataDirectory\(\)|\bAppInitMain\(\)|\bSetupServerArgs\(\)|\bLicenseInfo\(\)|g_wallet_init_interface|init.h

src/rpc/misc.cpp

@@ -7,7 +7,6 @@
 #include <clientversion.h>
 #include <core_io.h>
 #include <crypto/ripemd160.h>
-#include <init.h>
 #include <key_io.h>
 #include <validation.h>
 #include <httpserver.h>