[OE-core] [PATCH] ccache: upgrade 3.6 -> 3.7.1

[Richard Purdie]

On Tue, 2019-05-07 at 16:11 +0300, Adrian Bunk wrote:
> Remove backported patches.
> Switch to new download location.
> 
> Signed-off-by: Adrian Bunk <bunk at stusta.de>

This patch caused an unintended side effect which you can reproduce
with:

oe-selftest -r buildoptions.ImageOptionsTests.test_ccache_tool

Its the change from .gz to .xz which introduces circular dependencies
for ccache-native.

(one of the issues in 
https://autobuilder.yoctoproject.org/typhoon/#/builders/56/builds/456)

Cheers,

Richard