Fix incorrect method description

Author: jamis

lib/mongo/socket/ssl.rb

@@ -505,7 +505,6 @@ def extract_certs(text)
       end
 
       # Find the issuer certificate in the chain.
-      # If the issuer is not found, raise an error.
       def find_issuer(cert, cert_chain)
         cert_chain.find { |c| c.subject == cert.issuer }
       end