C++: Remove references to the deleted api.

Author: aschackmull

cpp/ql/lib/semmle/code/cpp/dataflow/RecursionPrevention.qll

@@ -19,7 +19,6 @@ import semmle.code.cpp.security.Security
 import semmle.code.cpp.valuenumbering.GlobalValueNumbering
 import semmle.code.cpp.ir.IR
 import semmle.code.cpp.ir.dataflow.TaintTracking
-import semmle.code.cpp.ir.dataflow.TaintTracking2
 import semmle.code.cpp.security.FlowSources
 import semmle.code.cpp.models.implementations.Strcat
 import ExecTaint::PathGraph