manifest: Fix qemu-kernel clone depth

Needed when using referenced environments

Change-Id: Idba847c0dd00cfb6e343e800d754c7e507c11794
diff --git a/default.xml b/default.xml
index 19b64bc..12eda98 100644
--- a/default.xml
+++ b/default.xml
@@ -535,7 +535,7 @@
   <project path="prebuilts/ndk" name="platform/prebuilts/ndk" groups="pdk" remote="aosp" revision="refs/tags/android-5.0.2_r1" />
   <project path="prebuilts/python/darwin-x86/2.7.5" name="platform/prebuilts/python/darwin-x86/2.7.5" groups="darwin" remote="aosp" revision="refs/tags/android-5.0.2_r1" />
   <project path="prebuilts/python/linux-x86/2.7.5" name="platform/prebuilts/python/linux-x86/2.7.5" groups="linux" remote="aosp" revision="refs/tags/android-5.0.2_r1" />
-  <project path="prebuilts/qemu-kernel" name="platform/prebuilts/qemu-kernel" groups="pdk" remote="aosp" revision="refs/tags/android-5.0.2_r1" />
+  <project path="prebuilts/qemu-kernel" name="platform/prebuilts/qemu-kernel" groups="pdk" clone-depth="1" remote="aosp" revision="refs/tags/android-5.0.2_r1" />
   <project path="prebuilts/sdk" name="platform/prebuilts/sdk" groups="pdk" remote="aosp" revision="refs/tags/android-5.0.2_r1" />
   <project path="prebuilts/tools" name="platform/prebuilts/tools" groups="pdk,tools" remote="aosp" revision="refs/tags/android-5.0.2_r1" />
   <project path="sdk" name="platform/sdk" remote="aosp" revision="refs/tags/android-5.0.2_r1" />