Make rational_test link to unit test lib, not test execution lib.

[SVN r33340]

status/Jamfile

@@ -164,7 +164,7 @@ subinclude libs/xpressive/test ;           # test-suite xpressive
 
     test-suite rational
         : [ run libs/rational/rational_example.cpp ]
-          [ run libs/rational/rational_test.cpp <lib>../libs/test/build/boost_test_exec_monitor ]
+          [ run libs/rational/rational_test.cpp <lib>../libs/test/build/boost_unit_test_framework ]
         ;
 
     subinclude libs/test/test ;