test: physical: Fix misc-unused-using-decls
```
../test/physical.cpp:74:18: error: using decl 'Throw' is unused [misc-unused-using-decls,-warnings-as-errors]
using ::testing::Throw;
^
/home/andrew/src/openbmc/phosphor-led-sysfs/build/../test/physical.cpp:74:18: note: remove the using
using ::testing::Throw;
~~~~~~~~~~~~~~~~~^~~~~~
```
Change-Id: Ia13ce426cd366ea3c13f691fc1f1f93d1aa173ec
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
diff --git a/test/physical.cpp b/test/physical.cpp
index 7656cb2..f9191a3 100644
--- a/test/physical.cpp
+++ b/test/physical.cpp
@@ -72,7 +72,6 @@
using ::testing::InSequence;
using ::testing::NiceMock;
using ::testing::Return;
-using ::testing::Throw;
TEST(Physical, ctor_none_trigger)
{