install: Only check ro.build.tags for user builds

Change-Id: I0623e3fc19eab3213f4ced41141bc46914af5417
diff --git a/install/install.cpp b/install/install.cpp
index f36a611..3b71096 100644
--- a/install/install.cpp
+++ b/install/install.cpp
@@ -198,7 +198,7 @@
   }
   const auto post_build = get_value(metadata, "post-build");
   const auto build_fingerprint = android::base::Tokenize(post_build, "/");
-  if (!build_fingerprint.empty()) {
+  if (!build_fingerprint.empty() && android::base::GetProperty("ro.build.type", "") == "user") {
     const auto& post_build_tag = build_fingerprint.back();
     const auto build_tag = android::base::GetProperty("ro.build.tags", "");
     if (build_tag != post_build_tag) {