C++: Fix bug in findMatchingDefinition.

In strict mode, don't give up after the first Document with candidates.

Change-Id: I62ba59708a3501b31f79d979b1a85bede875eccb
Reviewed-on: http://codereview.qt-project.org/5142
Reviewed-by: Leandro T. C. Melo <leandro.melo@nokia.com>

src/libs/cplusplus/CppDocument.cpp

@@ -844,9 +844,11 @@ Symbol *Snapshot::findMatchingDefinition(Symbol *declaration, bool strict) const
                 }
             }
 
-            if (!strict && ! best)
-                best = viableFunctions.first();
+            if (strict && ! best)
+                continue;
 
+            if (! best)
+                best = viableFunctions.first();
             return best;
         }
     }