segfault on delete locked segments.

[Franck78]

Draw 2 independent segments
Select the area
'E' edit set locked attribut, 'OK'
(they are still selected)
Press delete , bam.

If you move them before then it's ok, Kicad asks for 'double delete'

Application: KiCad
Version: 5.1.4, release build
Libraries:
    wxWidgets 3.0.2
    libcurl/7.37.0 OpenSSL/1.0.2j zlib/1.2.8 libidn/1.28 libssh2/1.4.3
Platform: Linux 4.4.180-102-default x86_64, 64 bit, Little endian, wxGTK
Build Info:
    wxWidgets: 3.0.2 (wchar_t,STL containers,compatible with 2.8) GTK+ 2.24
    Boost: 1.61.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.37.0
    Compiler: GCC 4.8.5 with C++ ABI 1002

Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_PYTHON3=OFF
    KICAD_SCRIPTING_WXPYTHON=ON
    KICAD_SCRIPTING_WXPYTHON_PHOENIX=OFF
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=OFF