Fix typo when parsing external platform version from Settings.

May fix http://b/2569139

Change-Id: I437f614fd25512bd461812feddb091edcd12ccb7
diff --git a/services/java/com/android/server/PackageManagerService.java b/services/java/com/android/server/PackageManagerService.java
index 076b0e2..e9e83d9 100644
--- a/services/java/com/android/server/PackageManagerService.java
+++ b/services/java/com/android/server/PackageManagerService.java
@@ -8802,7 +8802,7 @@
                             }
                             String external = parser.getAttributeValue(null, "external");
                             if (external != null) {
-                                mInternalSdkPlatform = Integer.parseInt(external);
+                                mExternalSdkPlatform = Integer.parseInt(external);
                             }
                         } catch (NumberFormatException e) {
                         }
@@ -9952,4 +9952,3 @@
                android.provider.Settings.Secure.DEFAULT_INSTALL_LOCATION, PackageHelper.APP_INSTALL_AUTO);
    }
 }
-