Fix build

Build is now failing with:
../../include/beecrypt/c++/util/AbstractSet.h: In instantiation of 'bool beecrypt::util::AbstractSet<E>::equals(const beecryp
t::lang::Object*) const [with E = beecrypt::util::Map<beecrypt::lang::Object, beecrypt::lang::Object>::Entry]':
Properties.cxx:228:1:   required from here
../../include/beecrypt/c++/util/AbstractSet.h:59:27: error: 'containsAll' was not declared in this scope, and no declarations
 were found by argument-dependent lookup at the point of instantiation [-fpermissive]
../../include/beecrypt/c++/util/AbstractSet.h:59:27: note: declarations in dependent base 'beecrypt::util::AbstractCollection
<beecrypt::util::Map<beecrypt::lang::Object, beecrypt::lang::Object>::Entry>' are not found by unqualified lookup
../../include/beecrypt/c++/util/AbstractSet.h:59:27: note: use 'this->containsAll' instead

[ may be due to gcc 4.7 ]

so, do as advised and add 'this->'

Signed-off-by: Arnaud Patard <rtp@mageia.org>
Index: beecrypt-4.2.1/include/beecrypt/c++/util/AbstractSet.h
===================================================================
--- beecrypt-4.2.1.orig/include/beecrypt/c++/util/AbstractSet.h
+++ beecrypt-4.2.1/include/beecrypt/c++/util/AbstractSet.h
@@ -56,7 +56,7 @@ namespace beecrypt {
 					if (c->size() != size())
 						return false;
 
-					return containsAll(*c);
+					return this->containsAll(*c);
 				}
 				return false;
 			}