build: force CRCCheck in Windows installer

Otherwise a user can pass /NCRC on the command line and bypass the
crc check, meaning they could install a potentially corrupted
installer.

Author: fanquake

share/setup.nsi.in

@@ -53,7 +53,7 @@ Var StartMenuGroup
 
 # Installer attributes
 InstallDir $PROGRAMFILES64\Bitcoin
-CRCCheck on
+CRCCheck force
 XPStyle on
 BrandingText " "
 ShowInstDetails show