Update iovec to a version with no winapi dependency

Author: danielframpton

Cargo.lock

@@ -1581,12 +1581,11 @@ dependencies = [
 
 [[package]]
 name = "iovec"
-version = "0.1.2"
+version = "0.1.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dbe6e417e7d0975db6512b90796e8ce223145ac4e33c377e4a42882a0e88bb08"
+checksum = "b2b3ea6ff95e175473f8ffe6a7eb7c00d054240321b84c57051175fe3c1e075e"
 dependencies = [
  "libc",
- "winapi 0.2.8",
 ]
 
 [[package]]