bitbake: test/fetch: Switch u-boot based test to use our own mirror

The upstream servers are having issues so switch to our own shadow copy
of the repo.

(Bitbake rev: 8e2d1f8de055549b2101614d85454fcd1d0f94b2)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

bitbake/lib/bb/tests/fetch.py

@@ -1335,7 +1335,7 @@ class FetchLatestVersionTest(FetcherTest):
         # combination version pattern
         ("sysprof", "git://git.yoctoproject.org/sysprof.git;protocol=https;branch=master", "cd44ee6644c3641507fb53b8a2a69137f2971219", "")
             : "1.2.0",
-        ("u-boot-mkimage", "git://source.denx.de/u-boot/u-boot.git;branch=master;protocol=https", "62c175fbb8a0f9a926c88294ea9f7e88eb898f6c", "")
+        ("u-boot-mkimage", "git://git.yoctoproject.org/bbfetchtests-u-boot.git;branch=master;protocol=https", "62c175fbb8a0f9a926c88294ea9f7e88eb898f6c", "")
             : "2014.01",
         # version pattern "yyyymmdd"
         ("mobile-broadband-provider-info", "git://git.yoctoproject.org/mobile-broadband-provider-info.git;protocol=https;branch=master", "4ed19e11c2975105b71b956440acdb25d46a347d", "")