Try to discard sccache

Raúl's idea is that sccache is not taking into account the config.toml,
let's verify.

(cherry picked from commit d0b3942)

Author: Algunenano

contrib/corrosion-cmake/config.toml.in

@@ -7,7 +7,6 @@ CXXFLAGS = "@RUST_CXXFLAGS@"
 [build]
 rustflags = @RUSTFLAGS@
 rustdocflags = @RUSTFLAGS@
-@RUSTCWRAPPER@
 
 [unstable]
 @RUST_CARGO_BUILD_STD@