Fixed fish_prompt not displaying $status
Fixed fish_prompt not displaying $status

The virtualenv `fish_prompt` wrapper now ensures that the original `fish_prompt` correctly displays the `$status` of the last command.
techtonik/virtualenv,Lyleo/virtualenv,Ivoz/virtualenv,francatore/virtualenv,dstufft/virtualenv,Lyleo/virtualenv,dstufft/virtualenv,vvtam/virtualenv,vvtam/virtualenv,francatore/virtualenv,Ivoz/virtualenv,techtonik/virtualenv