Updating extension via CLI shows undefined version

[sbatten]

Issue Type: Bug

1. Install outdated extension via vsix.
2. Update extension via CLI using --install-extension <extension-id> --force
   🐛 => Updating the Extension '<extension-id>' to a newer version undefined

VS Code version: Code - Insiders 1.28.0-insider (5ba5f14, 2018-09-26T07:32:21.753Z)
OS version: Windows_NT x64 10.0.17134

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-8650U CPU @ 1.90GHz (8 x 2112)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: disabled_software rasterization: enabled video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled
Memory (System)	15.93GB (7.82GB free)
Process Argv
Screen Reader	no
VM	0%