Global Symbol Library not initialized properly if first project opened is an existing project with project specific libraries (lp:#1809769)

[Original report](https://bugs.launchpad.net/bugs/1809769) created by **drojf (drojfjord)**
```
Normally, after you install kicad, and create a new project, then open the
schematic editor, you'll get the "Configure Global Symbol Library Table"
dialog. This will then initialize your symbol library table to the
defaults.

Expected Behavior:

If you open a project with project specific libraries after installing
Kicad, and choose to copy default libraries, the Global Symbol Library
Table should contain the default libraries.

Actual Behavior:

If you open a project with project specific libraries after installing
Kicad, the Global Symbol Library Table will contain the "Project Specific
Libraries" from the first project you open. None of default libraries are
copied.

If you open a project without project specific libraries, it seems to work
OK

EDIT:
I just noticed that the project specific libraries are stored in a file
called "sym-lib-table" in the project directory. I managed to reproduce the
issue even if there are no project specific libraries in the project, as
long as you have a "sym-lib-table" in your project folder containing no
entries in it. So I'm guessing Kicad is copying this file and using it as
the global defaults.

Reproduction instructions:

- With a working copy of Kicad, create a schematic project which has at
least one Project Specific library. I have provided two example projects
which cause the problem, just in case it's something to do with my setup
specifically. In my examples, the project specific library is located
adjacent to the project files (if that makes a difference).

- Delete or rename your 'global libraries' folder to simulate a fresh
install of Kicad. I'm on windows, so I delete the folder
`C:\Users\drojf\AppData\Roaming\kicad`. (Alternatively, do a fresh install
of Kicad on a machine which hasn't ever had Kicad installed.)

- Open the schematic project which was created earlier. This should cause
the 'Configure Global Symbol Library Table' dialog to pop up. Choose the
default option, "Copy default global symbol library table (recommended)".

- Now if you check the "Global Libraries", it will contain the "Project
Specific Libraries" from the project you just opened, instead of the
"default" Global Libraries. The global libraries will remain this way, even
after closing and opening Kicad again or making a new project.

NOTE: I delete the 'global libraries' folder to simulate having installed
Kicad from scratch, but I've seen it happen numerous times before when
installing Kicad the first time 'for real'.

I remember this happening in previous Kicad versions, I don't think it was
introduced in this particular build of Kicad.

Version Information:

Application: kicad
Version: (5.0.2)-1, release build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.61.1 OpenSSL/1.1.1 (WinSSL) zlib/1.2.11 brotli/1.0.6
libidn2/2.0.5 libpsl/0.20.2 (+libidn2/2.0.5) nghttp2/1.34.0
Platform: Windows 8 (build 9200), 64-bit edition, 64 bit, Little endian,
wxMSW
Build Info:
    wxWidgets: 3.0.4 (wchar_t,wx containers,compatible with 2.8)
    Boost: 1.68.0
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.61.1
    Compiler: GCC 8.2.0 with C++ ABI 1013

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
```
Original tags: first libraries run setup symbol

Story points: 14.0