Bug#975039: Cleaner work around for Evolution 3.38.3-1 which still fails to render emails

[Osamu Aoki]

After I posted previous workaround, I realize this can be done more
cleanly to get GUI icon start up to work.

I created /usr/local/bin/evolution as:

```
#!/bin/sh -e
WEBKIT_FORCE_SANDBOX=0 exec /usr/bin/evolution "$@"

```

Since my PATH setting is ordered as 
  /usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin
this nicely replace all invocation of evolution without full path.

Osamu