windows vendored openssl doesn't statically link

_Moving here discussion from sfackler/rust-openssl#1398_

Seems that on MSVC windows the library are always built as dlls, unless the `crt-static` feature is enabled. [This piece of code](https://github.com/alexcrichton/openssl-src-rs/blob/master/src/lib.rs#L151) is omitting the `no-shared` configuration argument to the `Configure` script, resulting in dll being built and binaries linked against `openssl-sys` still requiring dll to be installed or available in PATH.

Forcing that `no-static` argument, allows vendored openssl to link correctly.

I don't think that the [above linked configuration](https://github.com/alexcrichton/openssl-src-rs/blob/master/src/lib.rs#L151) is correct: from what I read, `crt-static` is something related to the base windows libraries and should not affect the linking of a library such as openssl; besides, openssl-sys already takes care of telling cargo to link correctly the windows runtime by properly adding:
```
cargo:rustc-link-lib=static=libssl
cargo:rustc-link-lib=static=libcrypto
cargo:rustc-link-lib=dylib=gdi32
cargo:rustc-link-lib=dylib=user32
cargo:rustc-link-lib=dylib=crypt32
cargo:rustc-link-lib=dylib=ws2_32
cargo:rustc-link-lib=dylib=advapi32
```