Rename the Default* constants in java/config.

These values are used in two out of the many possible sdk_version
configurations, and therefore weren't really defaults in any
meaningful sense. Giving them more descriptive names makes the code
easier to follow.

Bug: 157640067
Test: m nothing
Change-Id: Icf38a9c0be2606ad0478929e1b40dfcee36cddef
diff --git a/java/droiddoc.go b/java/droiddoc.go
index e14814b..61bdc88 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -441,10 +441,10 @@
 	if ctx.Device() {
 		sdkDep := decodeSdkDep(ctx, sdkContext(j))
 		if sdkDep.useDefaultLibs {
-			ctx.AddVariationDependencies(nil, bootClasspathTag, config.DefaultBootclasspathLibraries...)
-			ctx.AddVariationDependencies(nil, systemModulesTag, config.DefaultSystemModules)
+			ctx.AddVariationDependencies(nil, bootClasspathTag, config.LegacyCorePlatformBootclasspathLibraries...)
+			ctx.AddVariationDependencies(nil, systemModulesTag, config.LegacyCorePlatformSystemModules)
 			if sdkDep.hasFrameworkLibs() {
-				ctx.AddVariationDependencies(nil, libTag, config.DefaultLibraries...)
+				ctx.AddVariationDependencies(nil, libTag, config.FrameworkLibraries...)
 			}
 		} else if sdkDep.useModule {
 			ctx.AddVariationDependencies(nil, bootClasspathTag, sdkDep.bootclasspath...)