tests: fix warnings

Fix a couple of warnings:

-Werror=unused-parameter

so we can use meson's warning_level=3 and -Werror without build
failures.

Change-Id: I1c3930226b34d6beeb7c5fb5ce135c722d3e8758
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/test/sensor_unittest.cpp b/test/sensor_unittest.cpp
index 3a446b2..15a4807 100644
--- a/test/sensor_unittest.cpp
+++ b/test/sensor_unittest.cpp
@@ -88,7 +88,7 @@
     EXPECT_CALL(env::mockEnv, get(StrEq("GPIO_temp5"))).WillOnce(Return("5"));
 
     EXPECT_CALL(gMock, build(StrEq("chipA"), StrEq("5")))
-        .WillOnce(Invoke([&](const std::string& chip, const std::string& line) {
+        .WillOnce(Invoke([&](const std::string&, const std::string&) {
             return std::move(handleMock);
         }));