InstallPackageHelper: fiX the NPE problem.

 Install the renamed apk,use the new name to getPackageLPr may be null,so we should make a null judgment.

Test: monkey test
Flag: EXEMPT bugfix
Bug: 386727719
Change-Id: Ia41a401bceaa13889ea66f5e3e337b99e3e4b799
diff --git a/services/core/java/com/android/server/pm/InstallPackageHelper.java b/services/core/java/com/android/server/pm/InstallPackageHelper.java
index f449126..d4efb5c 100644
--- a/services/core/java/com/android/server/pm/InstallPackageHelper.java
+++ b/services/core/java/com/android/server/pm/InstallPackageHelper.java
@@ -1387,7 +1387,7 @@
         boolean systemApp = false;
         boolean replace = false;
         synchronized (mPm.mLock) {
-            final PackageSetting ps = mPm.mSettings.getPackageLPr(pkgName);
+            PackageSetting ps = mPm.mSettings.getPackageLPr(pkgName);
             // Check if installing already existing package
             if ((installFlags & PackageManager.INSTALL_REPLACE_EXISTING) != 0) {
                 String oldName = mPm.mSettings.getRenamedPackageLPr(pkgName);
@@ -1398,14 +1398,15 @@
                     // name.  We must continue using the original name, so
                     // rename the new package here.
                     parsedPackage.setPackageName(oldName);
-                    pkgName = parsedPackage.getPackageName();
-                    replace = true;
+                    pkgName = oldName;
+                    ps = mPm.mSettings.getPackageLPr(oldName);
                     if (DEBUG_INSTALL) {
                         Slog.d(TAG, "Replacing existing renamed package: oldName="
                                 + oldName + " pkgName=" + pkgName);
                     }
-                } else if (ps != null) {
-                    // This package, under its official name, already exists
+                }
+                if (ps != null) {
+                    // This package, under its official name or its old name, already exists
                     // on the device; we should replace it.
                     replace = true;
                     if (DEBUG_INSTALL) Slog.d(TAG, "Replace existing package: " + pkgName);