Avoid using incomplete types with std containers

...which is explicitly supported by Boost.Container though, but we cannot use
boost::container::map here as Boost.Container is only available since Boost 1.48
and our base is 1.47 still.  However, there appears no need for Children to be
sorted, and std::unordered_map (and thus boost::unordered_map) requires that
pointers to elements are not invalidated by insertions, which we do require.

Change-Id: I70ad6f40318d2bafae53ebb67d84c1c89a7d68f6

configmgr/source/modifications.hxx

@@ -22,8 +22,7 @@
 
 #include "sal/config.h"
 
-#include <map>
-
+#include "boost/unordered_map.hpp"
 #include "boost/noncopyable.hpp"
 
 #include "path.hxx"
@@ -34,7 +33,7 @@ namespace configmgr {
 class Modifications: private boost::noncopyable {
 public:
     struct Node {
-        typedef std::map< OUString, Node > Children;
+        typedef boost::unordered_map<OUString, Node, OUStringHash> Children;
 
         Children children;
     };