BF: install system side packages BEFORE venv etc

.appveyor.yml

@@ -145,6 +145,8 @@ init:
 install:
   # place a debug setup helper at a convenient location
   - cmd: copy tools\ci\appveyor_env_setup.bat C:\\datalad_debug.bat
+  # Missing system software
+  - sh: "[ -n \"$INSTALL_SYSPKGS\" ] && ( [ \"x${APPVEYOR_BUILD_WORKER_IMAGE}\" = \"xmacOS\" ] && brew install -q ${INSTALL_SYSPKGS} || { sudo apt-get update -y && sudo apt-get install --no-install-recommends -y ${INSTALL_SYSPKGS}; } ) || true"
   # If a particular Python version is requested, use env setup (using the
   # appveyor provided environments/installation). Note, these are broken
   # on the ubuntu images
@@ -161,8 +163,6 @@ install:
       python -m pip install datalad-installer
       )
   - sh: python -m pip install datalad-installer${DATALAD_INSTALLER_VERSION:-}
-  # Missing system software
-  - sh: "[ -n \"$INSTALL_SYSPKGS\" ] && ( [ \"x${APPVEYOR_BUILD_WORKER_IMAGE}\" = \"xmacOS\" ] && brew install -q ${INSTALL_SYSPKGS} || { sudo apt-get update -y && sudo apt-get install --no-install-recommends -y ${INSTALL_SYSPKGS}; } ) || true"
   # Install git-annex on windows, otherwise INSTALL_SYSPKGS can be used
   # deploy git-annex, if desired
   - cmd: IF DEFINED INSTALL_GITANNEX datalad-installer --sudo ok %INSTALL_GITANNEX%