Fix host header for connect proxy #2672

Job	Run time
Docs	1m 39s
Test	1m 3s
Lint	36s
build_versions (stable)	10s
Test (charset)	1m 5s
build_versions (beta)	19s
Test (cookies)	1m 17s
build_versions (1.71.1)	23s
Test	52s
cargo-deny (aarch64-apple-ios)	21s
Test (charset)	1m 2s
cargo-deny (aarch64-linux-android)	22s
Test (cookies)	1m 3s
Test (socks-proxy)	1m 3s
cargo-deny (i686-pc-windows-gnu)	20s
Test (socks-proxy)	51s
Test (gzip)	1m 7s
cargo-deny (i686-pc-windows-msvc)	22s
Test (gzip)	53s
Test (brotli)	1m 18s
cargo-deny (i686-unknown-linux-gnu)	19s
Test (brotli)	1m 9s
Test (json)	1m 15s
Test (json)	54s
Test (native-tls)	1m 22s
cargo-deny (wasm32-unknown-unknown)	19s
Test (native-tls)	1m 12s
Test (rustls-no-provider)	1m 2s
cargo-deny (x86_64-apple-darwin)	36s
cargo-deny (x86_64-apple-ios)	23s
cargo-deny (x86_64-pc-windows-gnu)	20s
cargo-deny (x86_64-pc-windows-msvc)	20s
cargo-deny (x86_64-unknown-linux-gnu)	20s
cargo-deny (x86_64-unknown-redox)	22s
	25m 59s

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