gst-devenv 1.20 issue

gistfile1.txt

Trying to use the 1.20 devenv just gives

```bash
0:00:00.001824389 294176 0x5594fe4b8e90 ERROR     GST_PLUGIN_LOADING gstpluginloader.c:442:gst_plugin_loader_try_helper: Spawning gst-plugin-scanner helper failed: Failed to execute child process “/usr/local/libexec/gstreamer-1.0/gst-plugin-scanner” (No such file or directory)

(gst-inspect-1.0:294176): GStreamer-WARNING **: 10:22:46.304: External plugin loader failed. This most likely means that the plugin loader helper binary was not found or could not be run. You might need to set the GST_PLUGIN_SCANNER environment variable if your setup is unusual. This should normally not be required though.
Fatal Python error: init_sys_streams: <stdin> is a directory, cannot continue
Python runtime state: core initialized

Current thread 0x00007f5a197f0b80 (most recent call first):
  <no Python frame>
```