Merge #11414: [docs] Remove partial gitian build instructions from descriptors dir.

bb174e1 [docs] Remove partial gitian instructions from descriptors dir (fanquake)

Pull request description:

  Cleanup after #11401.

Tree-SHA512: 9378463d3dd7a3c5b41388749002aef767581de28c92c19c89cc39c4e8ec5959f91d0232c6333e440c157d448be2f686dbcc7099aedd9510e4b36807690201fc

contrib/README.md

@@ -26,7 +26,7 @@ Contains files used to package bitcoind/bitcoin-qt
 for Debian-based Linux systems. If you compile bitcoind/bitcoin-qt yourself, there are some useful files here.
 
 ### [Gitian-descriptors](/contrib/gitian-descriptors) ###
-Notes on getting Gitian builds up and running using KVM.
+Files used during the gitian build process. For more information about gitian, see the [the Bitcoin Core documentation repository](https://github.com/bitcoin-core/docs).
 
 ### [Gitian-keys](/contrib/gitian-keys)
 PGP keys used for signing Bitcoin Core [Gitian release](/doc/release-process.md) results.

contrib/gitian-descriptors/README.md

@@ -1,65 +0,0 @@
-### Gavin's notes on getting Gitian builds up and running using KVM
-
-These instructions distilled from
-[https://help.ubuntu.com/community/KVM/Installation](https://help.ubuntu.com/community/KVM/Installation).
-
-You need the right hardware: you need a 64-bit-capable CPU with hardware virtualization support (Intel VT-x or AMD-V). Not all modern CPUs support hardware virtualization.
-
-You probably need to enable hardware virtualization in your machine's BIOS.
-
-You need to be running a recent version of 64-bit-Ubuntu, and you need to install several prerequisites:
-
-	sudo apt-get install ruby apache2 git apt-cacher-ng python-vm-builder qemu-kvm
-
-Sanity checks:
-
-	sudo service apt-cacher-ng status  # Should return apt-cacher-ng is running
-	ls -l /dev/kvm   # Should show a /dev/kvm device
-
-
-Once you've got the right hardware and software:
-
-    git clone git://github.com/bitcoin/bitcoin.git
-    git clone git://github.com/devrandom/gitian-builder.git
-    mkdir gitian-builder/inputs
-    cd gitian-builder/inputs
-
-    # Create base images
-    cd gitian-builder
-    bin/make-base-vm --suite trusty --arch amd64
-    cd ..
-
-    # Get inputs (see doc/release-process.md for exact inputs needed and where to get them)
-    ...
-
-    # For further build instructions see doc/release-process.md
-    ...
-
----------------------
-
-`gitian-builder` now also supports building using LXC. See
-[help.ubuntu.com](https://help.ubuntu.com/14.04/serverguide/lxc.html)
-for how to get LXC up and running under Ubuntu.
-
-If your main machine is a 64-bit Mac or PC with a few gigabytes of memory
-and at least 10 gigabytes of free disk space, you can `gitian-build` using
-LXC running inside a virtual machine.
-
-Here's a description of Gavin's setup on OSX 10.6:
-
-1. Download and install VirtualBox from [https://www.virtualbox.org/](https://www.virtualbox.org/)
-
-2. Download the 64-bit Ubuntu Desktop 12.04 LTS .iso CD image from
-   [http://www.ubuntu.com/](http://www.ubuntu.com/)
-
-3. Run VirtualBox and create a new virtual machine, using the Ubuntu .iso (see the [VirtualBox documentation](https://www.virtualbox.org/wiki/Documentation) for details). Create it with at least 2 gigabytes of memory and a disk that is at least 20 gigabytes big.
-
-4. Inside the running Ubuntu desktop, install:
-
-		sudo apt-get install debootstrap lxc ruby apache2 git apt-cacher-ng python-vm-builder
-
-5. Still inside Ubuntu, tell gitian-builder to use LXC, then follow the "Once you've got the right hardware and software" instructions above:
-
-		export USE_LXC=1
-		git clone git://github.com/bitcoin/bitcoin.git
-		... etc