tests: annotate qrexec EOF tests with expected failure

EOF transmission actually doesn't work in some cases in R2. It is rather
hard to change without introducing big changes (which we don't want to
do in R2). It should be fixed in R3.

BTW The said changes are in my qrexec-sockets branch in core-agent-linux
and linux-utils (then application should use shutdown(2) instead of
close). Alternatively qrexec-agent can use PAM directly (instead of
calling "su"). This is also implemented (pam branch in
core-agent-linux), but IMO it isn't the way to go (reimplementing "su"
in qrexec-agent code).

tests/vm_qrexec_gui.py

@@ -143,6 +143,7 @@ class VmRunningTests(unittest.TestCase):
         elif result.value == 2:
             self.fail("Some data was printed to stderr")
 
+    @unittest.expectedFailure
     def test_051_qrexec_simple_eof_reverse(self):
         """Test for EOF transmission VM->dom0"""
         result = multiprocessing.Value('i', 0)
@@ -210,6 +211,7 @@ class VmRunningTests(unittest.TestCase):
         if result.value == 1:
             self.fail("Received data differs from what was expected")
 
+    @unittest.expectedFailure
     def test_053_qrexec_vm_service_eof_reverse(self):
         """Test for EOF transmission VM(src)<-VM(dst)"""
         result = multiprocessing.Value('i', 0)