tesla_dashcam: ffmpeg errors after 0.1.10 to 0.1.12

This maybe related to #51 but there are enough details that differ that I think it’s worth posting it separately.

System setup is as follows:

• machine 1 is a linux box running Ubuntu 19.04. This machine has tesla_dashcam installed via pip.
• machine 2 is a mac with a large disk array attached and shared via SMB. This machine holds all the movie files, and is often where they are copied from the TeslaCam USB.

Machine 1 has the SMB folder mounted and I have opened a terminal window and cd’d into the share, as such, $CWD is /run/user/1000/gvfs/smb-share:server=machine2.local,share=storage/TeslaCam. In that terminal I run tesla_dashcam as such: tesla_dashcam --merge --compression veryslow --quality HIGH --output Processed/ SavedClips/. Previously, running 0.1.10 I was able to process the videos successfully with this configuration. Tonight I ran for the first time in a couple months (finally filled the new, larger, USB drive I got after they flagged the old one as too slow.) and was informed there was a new build of tesla_dashcam. So I updated to 0.1.12, and now when I run as above I get this error:

	Processing 6 clips in folder SavedClips/2019-05-06_18-37-50 (3/238)
		Processing clip 1/6 from 05/06/19 18:30:40 and 59 seconds long.
		Processing clip 2/6 from 05/06/19 18:31:41 and 59 seconds long.
		Processing clip 3/6 from 05/06/19 18:32:41 and 59 seconds long.
		Processing clip 4/6 from 05/06/19 18:33:41 and 59 seconds long.
		Processing clip 5/6 from 05/06/19 18:34:42 and 59 seconds long.
		Processing clip 6/6 from 05/06/19 18:36:43 and 13 seconds long.
		Creating movie Processed/2019-05-06T18-30-40_2019-05-06T18-36-56.mp4, please be patient.
		Error trying to create movie Processed/2019-05-06T18-30-40_2019-05-06T18-36-56.mp4. RC: 1
		Command: ['ffmpeg', '-f', 'concat', '-safe', '0', '-i', '/tmp/tmpr00thmma.txt', '-i', '/tmp/tmpypqx88qr.txt', '-map_metadata', '1', '-map_chapters', '1', '-movflags', '+faststart', '-c', 'copy', '-y', 'Processed/2019-05-06T18-30-40_2019-05-06T18-36-56.mp4']
		Error: b"ffmpeg version 4.1.3-0ubuntu1 Copyright (c) 2000-2019 the FFmpeg developers\n  built with gcc 8 (Ubuntu 8.3.0-6ubuntu1)\n  configuration: --prefix=/usr --extra-version=0ubuntu1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared\n  libavutil      56. 22.100 / 56. 22.100\n  libavcodec     58. 35.100 / 58. 35.100\n  libavformat    58. 20.100 / 58. 20.100\n  libavdevice    58.  5.100 / 58.  5.100\n  libavfilter     7. 40.101 /  7. 40.101\n  libavresample   4.  0.  0 /  4.  0.  0\n  libswscale      5.  3.100 /  5.  3.100\n  libswresample   3.  3.100 /  3.  3.100\n  libpostproc    55.  3.100 / 55.  3.100\n[concat @ 0x55971b2ecb40] Impossible to open '/tmp/Processed/2019-05-06_18-31.mp4'\n/tmp/tmpr00thmma.txt: No such file or directory\n"