Revert "Change linker config variable: VNDK_VER"

This reverts commit e30a7f5d1f00f4571c4a6ea9766fd22a6be27904.

Reason for revert: some targets are broken

Bug: 142773030
Change-Id: I651ef00a9d1aaac6f0119d31712fb588d8aa68f0
diff --git a/linker/linker_config.cpp b/linker/linker_config.cpp
index 450d0e6..46c91a3 100644
--- a/linker/linker_config.cpp
+++ b/linker/linker_config.cpp
@@ -408,7 +408,7 @@
       params.push_back({ "SDK_VER", buf });
     }
 
-    static std::string vndk = Config::get_vndk_version_string("");
+    static std::string vndk = Config::get_vndk_version_string('-');
     params.push_back({ "VNDK_VER", vndk });
 
     for (auto& path : paths) {
@@ -596,11 +596,11 @@
   return true;
 }
 
-std::string Config::get_vndk_version_string(const std::string& prefix) {
+std::string Config::get_vndk_version_string(const char delimiter) {
   std::string version = android::base::GetProperty("ro.vndk.version", "");
   if (version != "" && version != "current") {
-    //add the prefix in front of the string and return it.
-    return version.insert(0, prefix);
+    //add the delimiter char in front of the string and return it.
+    return version.insert(0, 1, delimiter);
   }
   return "";
 }