C++: Remove redundant case from shouldPrintDeclaration

A configuration should always exist, because it does not have a charpred
that could prevent this.

Author: jketema

cpp/ql/lib/semmle/code/cpp/Print.qll

@@ -8,8 +8,6 @@ private import PrintAST
 private predicate shouldPrintDeclaration(Declaration decl) {
   not (decl instanceof Function or decl instanceof GlobalOrNamespaceVariable)
   or
-  not exists(PrintAstConfiguration c)
-  or
   exists(PrintAstConfiguration config | config.shouldPrintDeclaration(decl))
 }