Don't install header libraries

Use library.shared() instead of !ctx.static() to avoid installing
header libraries when handling installation in soong.

Test: check build.ninja for installed .a files
Change-Id: I8c59d5845dd32419644b7ccdab3c341bc4bf3617

cc/library.go

@@ -604,7 +604,7 @@ func (library *libraryDecorator) toc() android.OptionalPath {
 }
 
 func (library *libraryDecorator) install(ctx ModuleContext, file android.Path) {
-	if !ctx.static() {
+	if library.shared() {
 		library.baseInstaller.install(ctx, file)
 	}
 }