Attempt to fix OpenSSL build under nix

[link2xt]

Trying to use alexcrichton/openssl-src-rs#236

This fails with a new error:

$ nix build .#deltachat-rpc-server-x86_64-linux
error: builder for '/nix/store/cbk8amj58m8znxlcx0p4d0fxhq7grkc4-deltachat-deps-1.136.0.drv' failed with exit code 101;
       last 25 log lines:
       >   cargo:rerun-if-env-changed=RANLIBFLAGS_x86_64-unknown-linux-musl
       >   RANLIBFLAGS_x86_64-unknown-linux-musl = None
       >   cargo:rerun-if-env-changed=RANLIBFLAGS_x86_64_unknown_linux_musl
       >   RANLIBFLAGS_x86_64_unknown_linux_musl = None
       >   cargo:rerun-if-env-changed=TARGET_RANLIBFLAGS
       >   TARGET_RANLIBFLAGS = None
       >   cargo:rerun-if-env-changed=RANLIBFLAGS
       >   RANLIBFLAGS = None
       >   running cd "/build/dummy-src/target/x86_64-unknown-linux-musl/release/build/openssl-sys-462ecfdd0a9cb8e3/out/openssl-build/build/src" && env -u CROSS_COMPILE AR="ar" CC="/nix/store/j9zmg94bapyyv5pni864cl4rqwsp03h3-x86_64-unknown-linux-musl-gcc-wrapper-13.2.0/bin/x86_64-unknown-linux-musl-cc" RANLIB="ranlib" "perl" "./Configure" "--prefix=/build/dummy-src/target/x86_64-unknown-linux-musl/release/build/openssl-sys-462ecfdd0a9cb8e3/out/openssl-build/install" "--openssldir=/usr/local/ssl" "no-dso" "no-shared" "no-ssl3" "no-tests" "no-comp" "no-zlib" "no-zlib-dynamic" "--libdir=lib" "no-md2" "no-rc5" "no-weak-ssl-ciphers" "no-camellia" "no-idea" "no-seed" "no-engine" "no-async" "linux-x86_64" "-O2" "-ffunction-sections" "-fdata-sections" "-fPIC" "-m64" "-DOPENSSL_NO_SECURE_MEMORY"
       >
       >   --- stderr
       >   Can't open perl script "./Configure": No such file or directory
       >   thread 'main' panicked at /nix/store/fqvrp4b4k0fx6gyigxj622ibhrg6gifa-git-dependencies/openssl-src-300.2.3+3.2.1-link2xt_copy-symlink/src/lib.rs:616:9:
       >
       >
       >
       >   Error configuring OpenSSL build:
       >       Command: cd "/build/dummy-src/target/x86_64-unknown-linux-musl/release/build/openssl-sys-462ecfdd0a9cb8e3/out/openssl-build/build/src" && env -u CROSS_COMPILE AR="ar" CC="/nix/store/j9zmg94bapyyv5pni864cl4rqwsp03h3-x86_64-unknown-linux-musl-gcc-wrapper-13.2.0/bin/x86_64-unknown-linux-musl-cc" RANLIB="ranlib" "perl" "./Configure" "--prefix=/build/dummy-src/target/x86_64-unknown-linux-musl/release/build/openssl-sys-462ecfdd0a9cb8e3/out/openssl-build/install" "--openssldir=/usr/local/ssl" "no-dso" "no-shared" "no-ssl3" "no-tests" "no-comp" "no-zlib" "no-zlib-dynamic" "--libdir=lib" "no-md2" "no-rc5" "no-weak-ssl-ciphers" "no-camellia" "no-idea" "no-seed" "no-engine" "no-async" "linux-x86_64" "-O2" "-ffunction-sections" "-fdata-sections" "-fPIC" "-m64" "-DOPENSSL_NO_SECURE_MEMORY"
       >       Exit status: exit status: 2
       >
       >
       >
       >   note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
       > warning: build failed, waiting for other jobs to finish...
       > [naersk] cargo returned with exit code 101, exiting
       For full logs, run 'nix log /nix/store/cbk8amj58m8znxlcx0p4d0fxhq7grkc4-deltachat-deps-1.136.0.drv'.
error: 1 dependencies of derivation '/nix/store/i31jwq5zp7smcf26fl1pvk2qy7l6b88x-deltachat-1.136.0.drv' failed to build

This is likely due to nix-community/naersk#287

$ ls /nix/store/fqvrp4b4k0fx6gyigxj622ibhrg6gifa-git-dependencies/openssl-src-300.2.3+3.2.1-link2xt_copy-symlink/src
lib.rs
$ ls /nix/store/fqvrp4b4k0fx6gyigxj622ibhrg6gifa-git-dependencies/openssl-src-300.2.3+3.2.1-link2xt_copy-symlink/openssl

Seems openssl submodule is not cloned in case of git dependency.