Change ramdisk-recovery.img Image.gz file key same as file name.

Make the file key same as file name will make it possible to use the
additional-files-filter to download the file.

Test: None
Change-Id: I2a6886ef16eb578d928de12100b62065c50b4d64
diff --git a/src/com/android/tradefed/targetprep/GkiDeviceFlashPreparer.java b/src/com/android/tradefed/targetprep/GkiDeviceFlashPreparer.java
index 8ab27d6..09ff964 100644
--- a/src/com/android/tradefed/targetprep/GkiDeviceFlashPreparer.java
+++ b/src/com/android/tradefed/targetprep/GkiDeviceFlashPreparer.java
@@ -49,8 +49,8 @@
     private static final String GKI_BOOT_IMG = "gki_boot.img";
     private static final String MKBOOTIMG = "mkbootimg";
     private static final String OTATOOLS_ZIP = "otatools.zip";
-    private static final String RAMDISK_RECOVERY_IMG = "ramdisk_recovery.img";
-    private static final String KERNEL_IMAGE = "kernel_image"; // The Image.gz file key
+    private static final String RAMDISK_RECOVERY_IMG = "ramdisk-recovery.img";
+    private static final String KERNEL_IMAGE = "Image.gz";
     private static final String VENDOR_BOOT_IMG = "vendor_boot.img";
     private static final String DTBO_IMG = "dtbo.img";
     // Wait time for device state to stablize in millisecond