pcbnew netlist import inconsistencies 'dry' vs 'real' run (lp:#1814883)

[Original report](https://bugs.launchpad.net/bugs/1814883) created by **Otto Mikkonen (ottomaani138)**
```
PCBNew netlist import shows different results on "dry" run versus the
actual run.

Example for encountered issue

"dry run"

Info: Changing component path "U7:/5B4DF991/5D2154A2" to
"/5B4DF991/5D34F6E2".
Info: Checking netlist symbol footprint
"U7:/5B4DF991/5D34F6E2:Package_SO:SOIC-8_3.9x4.9mm_P1.27mm".
Replacing symbol "U7:/5B4DF991/5D2154A2" footprint
"Package_TO_SOT_SMD:SOT-23-5" with "Package_SO:SOIC-8_3.9x4.9mm_P1.27mm".
Changing footprint "U7:/5B4DF991/5D2154A2" pad "5" net name from "VDD" to
"GNDA".
Changing footprint "U7:/5B4DF991/5D2154A2" pad "4" net name from
"Net-(R26-Pad2)" to "VEE".
Changing footprint "U7:/5B4DF991/5D2154A2" pad "3" net name from
"Net-(R25-Pad1)" to "GNDA".
Changing footprint "U7:/5B4DF991/5D2154A2" pad "2" net name from "VEE" to
"Net-(C28-Pad2)".
Changing footprint "U7:/5B4DF991/5D2154A2" pad "1" net name from
"/core-1/comp-out" to "/core-1/lin-cv-mix".
Changing footprint "U7:/5B4DF991/5D2154A2" value from "TLV171" to
"opa2180".
Error: Component "U7" pad "8" not found in footprint
"Package_TO_SOT_SMD:SOT-23-5"
Error: Component "U7" pad "6" not found in footprint
"Package_TO_SOT_SMD:SOT-23-5"
Error: Component "U7" pad "7" not found in footprint
"Package_TO_SOT_SMD:SOT-23-5"

-> Notice the error of missing pads on U7 footprint. The claimed footprint
(SOT-23) is wrong and is from an older netlist.

"actual run"

Info: Checking netlist symbol footprint
"U7:/5B4DF991/5D34F6E2:Package_SO:SOIC-8_3.9x4.9mm_P1.27mm".
Info: Changing component path "U7:/5B4DF991/5D2154A2" to
"/5B4DF991/5D34F6E2".
Changing footprint "U7:/5B4DF991/5D34F6E2" pad "2" net name from "" to
"Net-(C28-Pad2)".
Replacing symbol "U7:/5B4DF991/5D2154A2" footprint
"Package_TO_SOT_SMD:SOT-23-5" with "Package_SO:SOIC-8_3.9x4.9mm_P1.27mm".
Changing footprint "U7:/5B4DF991/5D34F6E2" pad "1" net name from "" to
"/core-1/lin-cv-mix".
Changing footprint "U7:/5B4DF991/5D34F6E2" pad "3" net name from "" to
"GNDA".
Changing footprint "U7:/5B4DF991/5D34F6E2" pad "4" net name from "" to
"VEE".
Changing footprint "U7:/5B4DF991/5D34F6E2" pad "5" net name from "" to
"GNDA".
Changing footprint "U7:/5B4DF991/5D34F6E2" pad "6" net name from "" to
"Net-(C29-Pad1)".
Changing footprint "U7:/5B4DF991/5D34F6E2" pad "7" net name from "" to
"Net-(C29-Pad2)".
Changing footprint "U7:/5B4DF991/5D34F6E2" pad "8" net name from "" to
"VDD".

The actual run is able to determine the correct footprint and thus the
error is not produced.

Attached full import reports for reference.

# # #

version info

Application: pcbnew
Version: 5.0.2-bee76a0~70~ubuntu18.04.1, release build
Libraries:
    wxWidgets 3.0.4
    libcurl/7.58.0 OpenSSL/1.1.0g zlib/1.2.11 libidn2/2.0.4 libpsl/0.19.1
(+libidn2/2.0.4) nghttp2/1.30.0 librtmp/2.3
Platform: Linux 4.15.0-43-generic 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: 1.65.1
    OpenCASCADE Community Edition: 6.9.1
    Curl: 7.58.0
    Compiler: GCC 7.3.0 with C++ ABI 1011
Build settings:
    USE_WX_GRAPHICS_CONTEXT=OFF
    USE_WX_OVERLAY=OFF
    KICAD_SCRIPTING=ON
    KICAD_SCRIPTING_MODULES=ON
    KICAD_SCRIPTING_WXPYTHON=OFF
    KICAD_SCRIPTING_ACTION_MENU=ON
    BUILD_GITHUB_PLUGIN=ON
    KICAD_USE_OCE=ON
    KICAD_USE_OCC=OFF
    KICAD_SPICE=ON
```

Story points: 10.0