Make channel monitor test optional

[daykin]

2. 0048-skip-non-loopback-iface-tests.patch

The channel monitor test has to be optional too. This can't be done in the pbuilder chroot environment during build process. Unfortunately github fails to upload the modfied patch, but the relevant part could look like this:

-TESTPROD_HOST += testPVAServer
-testPVAServer_SRCS += testPVAServer.cpp
-testHarness_SRCS += testPVAServer.cpp
-TESTS += testPVAServer
-
-TESTPROD_HOST += testChannelMonitor
-testChannelMonitor_SRCS += testChannelMonitor.cpp
-testHarness_SRCS += testChannelMonitor.cpp
-TESTS += testChannelMonitor
+# If there's an available interface to do this on
+ifneq ($(shell ip addr | grep MULTICAST | wc -l),0)
+ TESTPROD_HOST += testPVAServer
+ testPVAServer_SRCS += testPVAServer.cpp
+ testHarness_SRCS += testPVAServer.cpp
+ TESTS += testPVAServer
+
+ TESTPROD_HOST += testChannelMonitor
+ testChannelMonitor_SRCS += testChannelMonitor.cpp
+ testHarness_SRCS += testChannelMonitor.cpp
+ TESTS += testChannelMonitor
+endif

Originally posted by @chrschroeder in #41

[daykin]

change currently staged on #40