fixes #15177, the error message is now what it should have been (#15195)

lib/pure/net.nim

@@ -116,7 +116,7 @@ when defineSsl:
 
 else:
   type
-    SslContext* = void # TODO: Workaround #4797.
+    SslContext* = ref object # TODO: Workaround #4797.
 
 const
   BufferSize*: int = 4000 ## size of a buffered socket's buffer

lib/pure/smtp.nim

@@ -112,8 +112,7 @@ proc quitExcpt(smtp: Smtp, msg: string) =
 const compiledWithSsl = defined(ssl)
 
 when not defined(ssl):
-  type PSSLContext = ref object
-  let defaultSSLContext: PSSLContext = nil
+  let defaultSSLContext: SSLContext = nil
 else:
   var defaultSSLContext {.threadvar.}: SSLContext