Remove duplicate header

Remove duplicate header
Duplicate header (debug.h) causes make install to fail

TEST=run the build
BUG=none

Review URL: http://codereview.chromium.org/2050014
diff --git a/src/Makefile.am b/src/Makefile.am
index 09ddc5b..709ba19 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -30,7 +30,6 @@
 	$(HEADER_DIR)/object.h \
 	$(HEADER_DIR)/pendingcall.h \
 	$(HEADER_DIR)/server.h \
-	$(HEADER_DIR)/debug.h \
 	$(HEADER_DIR)/util.h \
 	$(HEADER_DIR)/refptr_impl.h \
 	$(HEADER_DIR)/introspection.h \