jdk error message should not mention the version

the version is checked elsewhere

Bug: 13362810
Change-Id: I91e322780d8422ae78b9a4dc8ee008b99f860404
diff --git a/core/config.mk b/core/config.mk
index 57076ac..fee5705 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -375,7 +375,7 @@
 
 ifneq ($(HOST_JDK_TOOLS_JAR),)
 ifeq ($(wildcard $(HOST_JDK_TOOLS_JAR)),)
-$(error Error: could not find jdk tools.jar, please install JDK6)
+$(error Error: could not find jdk tools.jar, please check if your JDK was installed correctly)
 endif
 endif