add dummy argument to CreateLike for particlecontainers to match the …

[srichers]

…signature for multifabs

Summary

Modify the CreateLike function in IntegratorBase so all template specializations have the same function signature.

Additional background

Used in initialize_stages called in, for example RKIntegrator.
Addresses #4656 I think.

Checklist

The proposed changes:

• fix a bug or incorrect behavior in AMReX
• add new capabilities to AMReX
• changes answers in the test suite to more than roundoff level
• are likely to significantly affect the results of downstream AMReX users
• include documentation in the code and/or rst files, if appropriate

[atmyers]

I suggest:

Suggested change

	static void CreateLike (amrex::Vector<std::unique_ptr<T> >& V, const T& Other, bool dummy = false)
	static void CreateLike (amrex::Vector<std::unique_ptr<T> >& V, const T& Other, bool /*dummy*/ = false)

to avoid unused parameter warnings.