Use upstream AOSP source rather than parent directory

Without this patch we receive lots of these errors:
fatal: repository 'https://github.com/platform/external/expat/' not found
fatal: repository 'https://github.com/platform/external/jacoco/' not found
...
Change-Id: I8bf74006538f35c428a2ace55fa88b30702b737c
Signed-off-by: Lee Jones <lee.jones@linaro.org>

default.xml

@@ -2,7 +2,7 @@
 <manifest>
 
   <remote  name="aosp"
-           fetch=".."
+           fetch="https://android.googlesource.com/"
            review="https://android-review.googlesource.com/" />
   <default revision="o-preview"
            remote="aosp"