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/net_processing.cpp

@@ -11,7 +11,6 @@
 #include <chainparams.h>
 #include <consensus/validation.h>
 #include <hash.h>
-#include <init.h>
 #include <validation.h>
 #include <merkleblock.h>
 #include <netmessagemaker.h>