Fix for gvm-init.sh error on GNU bash 4.2.45

removed invalid return statement causing gvm-init.sh to abort on GNU bash, version 4.2.45(1)-release (x86_64-pc-linux-gnu)
```
bash -x .gvim/bin/gvim-init.sh
...
.gvm/bin/gvm-init.sh: line 120: return: can only `return' from a function or sourced script
```