Emit 0 exit code for --version and similar operations
Emit 0 exit code for --version and similar operations

Fixes #2878

SingingTree/rustfmt,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,rust-lang/rustfmt,rust-lang/rustfmt,SingingTree/rustfmt,aidancully/rust,aidancully/rust,aidancully/rust,aidancully/rust