default mirror switch to caf

I HATE linaro mirror, wtf !!! This is second times...

Fetching projects:  97% (83/85)  error: Unable to find 943becc617c4a7f9c72bbed311961b6fd2ce1486 under http://android.git.linaro.org/git-ro/platform/prebuilt
Cannot obtain needed object 943becc617c4a7f9c72bbed311961b6fd2ce1486
error: Fetch failed.
error: Unable to find 4b19d50bf147bc4b22be9e43ff4efda90ee215da under http://android.git.linaro.org/git-ro/platform/frameworks/base
Cannot obtain needed object 4b19d50bf147bc4b22be9e43ff4efda90ee215da
while processing commit ecc35e680b1d5093c7f7cebce25117e6fb384b1c.
error: Fetch failed.
error: Cannot fetch platform/prebuilt
error: Cannot fetch platform/frameworks/base

Signed-off-by: coldnew <coldnew.tw@gmail.com>