Make dbus-sensors compile with clang-13

clang-13 finds a lot more warnings for unused variables than it used to,
and also picks up some warnings about errant std::moves that are in
place.

This commit fixes them.

Tested:
code compiles against clang-13

Signed-off-by: Ed Tanous <edtanous@google.com>
Change-Id: I80864287b7131acfe936c4b28afaf34ababb3029
diff --git a/src/ExternalSensor.cpp b/src/ExternalSensor.cpp
index 17f5300..745c65b 100644
--- a/src/ExternalSensor.cpp
+++ b/src/ExternalSensor.cpp
@@ -95,7 +95,7 @@
 
     // Connect ExternalSensor with Sensor
     auto weakThis = weak_from_this();
-    externalSetHook = std::move([weakThis]() {
+    externalSetHook = [weakThis]() {
         auto lockThis = weakThis.lock();
         if (lockThis)
         {
@@ -106,7 +106,7 @@
         {
             std::cerr << "ExternalSensor receive ignored, sensor gone\n";
         }
-    });
+    };
 }
 
 ExternalSensor::~ExternalSensor()