8023826: Typo in warning about obsolete source / target values

Reviewed-by: jjg, wmdietl
diff --git a/langtools/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java b/langtools/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java
index 6f7ce69..73d3b02 100644
--- a/langtools/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java
+++ b/langtools/src/share/classes/com/sun/tools/javac/main/JavaCompiler.java
@@ -446,7 +446,7 @@
             }
 
             if (target.compareTo(Target.JDK1_5) <= 0) {
-                log.warning(LintCategory.OPTIONS, "option.obsolete.target", source.name);
+                log.warning(LintCategory.OPTIONS, "option.obsolete.target", target.name);
                 obsoleteOptionFound = true;
             }