add-ons/locale: Remove unused auto_ptr

Change-Id: Ibe10945ce38dec3f4be229450ba32125539dfdd1
Reviewed-on: https://review.haiku-os.org/744
Reviewed-by: Adrien Destugues <pulkomandy@pulkomandy.tk>

src/add-ons/locale/catalogs/plaintext/Catalog.cpp

@@ -9,7 +9,6 @@
 #include <cstdio>
 #include <iostream>
 #include <fstream>
-#include <memory>
 #include <new>
 #include <sstream>
 #include <string>
@@ -33,7 +32,6 @@
 
 using BPrivate::HashMapCatalog;
 using BPrivate::PlainTextCatalog;
-using std::auto_ptr;
 using std::min;
 using std::max;
 using std::pair;