Deprecated old appveyor-mingw script

scripts/appveyor-mingw.sh

@@ -1,21 +0,0 @@
-#!/bin/sh
-set -e
-cd `dirname "$0"`/..
-if [ "$ARCH" = "i686" ]; then
-  f=i686-4.9.2-release-win32-sjlj-rt_v3-rev1.7z
-  if ! [ -e $f ]; then
-    curl -LsSO http://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win32/Personal%20Builds/mingw-builds/4.9.2/threads-win32/sjlj/$f
-  fi
-  7z x $f > /dev/null
-  mv mingw32 /MinGW
-else
-  f=x86_64-4.9.2-release-win32-seh-rt_v3-rev1.7z
-  if ! [ -e $f ]; then
-    curl -LsSO http://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win64/Personal%20Builds/mingw-builds/4.9.2/threads-win32/seh/$f
-  fi
-  7z x $f > /dev/null
-  mv mingw64 /MinGW
-fi
-cd build
-cmake .. -G"$GENERATOR"
-cmake --build . --config RelWithDebInfo