package/python-cryptography: requires RC4 support in openssl

Fixes:
http://autobuild.buildroot.net/results/988/98819c1e202ddd77a390c9063ad31ee0601fefbe/

The build error, afaics, first appeared in
http://autobuild.buildroot.net/results/a08/a087c27dbc92c643f607ca9c66977156778ff1a0//
after the bump to version 43.0.1 with buildroot commit
37c397c8b691495b21623b7d0a4d1e5ee7f0f61e which added chacha support when
building with libopenssl.

Signed-off-by: Bernd Kuhls <bernd@kuhls.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/python-cryptography/Config.in

@@ -3,6 +3,7 @@ config BR2_PACKAGE_PYTHON_CRYPTOGRAPHY
 	depends on BR2_PACKAGE_HOST_RUSTC_TARGET_ARCH_SUPPORTS
 	select BR2_PACKAGE_OPENSSL
 	select BR2_PACKAGE_LIBOPENSSL_ENABLE_CHACHA if BR2_PACKAGE_LIBOPENSSL
+	select BR2_PACKAGE_LIBOPENSSL_ENABLE_RC4 if BR2_PACKAGE_LIBOPENSSL
 	select BR2_PACKAGE_PYTHON_CFFI # runtime
 	help
 	  cryptography is a package designed to expose cryptographic