component/stunnel: Use openssl == 1.0

Since default openssl component is 1.1 and is not compatible with this
component, use openssl-1.0.

component/stunnel/buildout.cfg

@@ -13,7 +13,7 @@ configure-options =
   --enable-ipv6
   --disable-libwrap
   --disable-fips
-  --with-ssl=${openssl:location}
+  --with-ssl=${openssl-1.0:location}
 environment =
   CPPFLAGS=-I${zlib:location}/include
-  LDFLAGS=-Wl,-rpath=${openssl:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib
+  LDFLAGS=-Wl,-rpath=${openssl-1.0:location}/lib -L${zlib:location}/lib -Wl,-rpath=${zlib:location}/lib