Activating zone cutout without selection gets into a strange state

[John Beard]

If you activate the zone cutout tool (GAL mode) with the hotkey, but without a zone selected, you can get into a strange state:

1) Draw a zone
2) Escape to normal mode
3) Have nothing selected
4) Press the cutout HK (C)
5) The pencil appears
6) You can't draw a zone
7) You can't escape with Esc
8) Escape by selecting another tool and then normal mode

----

Application: pcbnew
Version: (6.0.0-rc1-dev-147-gf0c571769), release build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.60.0 OpenSSL/1.1.0h zlib/1.2.11 libidn2/2.0.5 libpsl/0.20.2 (+libidn2/2.0.4) nghttp2/1.31.1
Platform: Linux 4.17.2-1-ARCH x86_64, 64 bit, Little endian, wxGTK
Build Info:
    wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8) GTK+ 2.24
    Boost: 1.67.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.60.0
    Compiler: GCC 8.1.1 with C++ ABI 1012

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON

[Seth Hillbrand (sethh)]

@Tom- I fixed this as a side-effect of the fix for lp:1789195