Fix warnings in servicemanager and KeyCharacterMap

- Suppress unused parameter warnings.
- Remove a few unused parameters.
- Set the correct formatting for size_t log.

Bug: 26936282
Change-Id: I2e2acb15d1bc05c6ba09563a87d5baceebe7ebd9
diff --git a/cmds/servicemanager/Android.mk b/cmds/servicemanager/Android.mk
index 7ee0dd1..73c0367 100644
--- a/cmds/servicemanager/Android.mk
+++ b/cmds/servicemanager/Android.mk
@@ -1,7 +1,7 @@
 LOCAL_PATH:= $(call my-dir)
 
 svc_c_flags =	\
-	-Wall -Wextra \
+	-Wall -Wextra -Werror \
 
 ifneq ($(TARGET_USES_64_BIT_BINDER),true)
 ifneq ($(TARGET_IS_64_BIT),true)