Add prebuilts/manifest-merger to the manifest

Bug: 112607039
Test: empty project
Change-Id: I478e8cee8e7adacb0ca619150e41bb5ccce7ba9b
diff --git a/default.xml b/default.xml
index 93ae30f..9af6540 100644
--- a/default.xml
+++ b/default.xml
@@ -635,6 +635,7 @@
   <project path="prebuilts/jdk/jdk8" name="platform/prebuilts/jdk/jdk8" groups="pdk" clone-depth="1" />
   <project path="prebuilts/jdk/jdk9" name="platform/prebuilts/jdk/jdk9" groups="pdk" clone-depth="1" />
   <project path="prebuilts/libs/libedit" name="platform/prebuilts/libs/libedit" groups="pdk-cw-fs,pdk-fs" clone-depth="1" />
+  <project path="prebuilts/manifest-merger" name="platform/prebuilts/manifest-merger" groups="pdk" clone-depth="1" />
   <project path="prebuilts/maven_repo/android" name="platform/prebuilts/maven_repo/android" groups="pdk-cw-fs,pdk-fs" clone-depth="1" />
   <project path="prebuilts/maven_repo/bumptech" name="platform/prebuilts/maven_repo/bumptech" groups="pdk-cw-fs,pdk-fs" clone-depth="1" />
   <project path="prebuilts/maven_repo/google-play-service-client-libraries-3p" name="platform/prebuilts/maven_repo/google-play-service-client-libraries-3p" clone-depth="1" />