Move STS insecurity exception for more immediate response.

Author: mbax

src/main/java/org/kitteh/irc/client/library/Client.java

@@ -254,6 +254,7 @@ enum SecurityType {
              *
              * @param factory trust manager supplier
              * @return this builder
+             * @throws IllegalArgumentException if providing an insecure factory while the STS storage manager is set
              * @see #secure(boolean)
              */
             @NonNull Server secureTrustManagerFactory(@Nullable TrustManagerFactory factory);

src/main/java/org/kitteh/irc/client/library/defaults/DefaultBuilder.java

@@ -147,6 +147,9 @@ private class ServerImpl implements Server {
 
         @Override
         public @NonNull Server secureTrustManagerFactory(@Nullable TrustManagerFactory factory) {
+            if (DefaultBuilder.this.stsStorageManager != null) {
+                Sanity.truthiness(!SslUtil.isInsecure(factory), "Cannot use STS with an insecure trust manager.");
+            }
             DefaultBuilder.this.secureTrustManagerFactory = factory;
             return this;
         }