Can I disable https certificate check – curl library issue on server

On my shared hosting server the hosting company has an old version of OpenSSL.
As a result it has problems verifying https certificates. For WordPress updates I skip the SSL verify (core provides a filter for this).

I get the following error message:
[13-Dec-2015 01:16:29] 1. Trying to send backup file to S3 Service …
[13-Dec-2015 01:16:38] ERROR: S3 Service API: [curl] 35: error:0D0890A1:asn1 encoding routines:ASN1_verify:unknown message digest algorithm [url] https://BUCKET_NAME.s3-eu-west-1.amazonaws.com

I hacked a workaround: I changed https to http in two locations in inc/class-destination-s3.php

Diff:

--- inc/class-destination-s3.orig.php	2015-12-14 09:30:47.717190600 +0000
+++ inc/class-destination-s3.php	2015-12-14 09:30:45.227971000 +0000
@@ -27,7 +27,7 @@
 			case 'us-west-2':
 				return 'https://s3-us-west-2.amazonaws.com';
 			case 'eu-west-1':
-				return 'https://s3-eu-west-1.amazonaws.com';
+				return 'http://s3-eu-west-1.amazonaws.com';  // Was 'https://s3-eu-west-1.amazonaws.com';
 			case 'eu-central-1':
 				return 'https://s3-eu-central-1.amazonaws.com';
 			case 'ap-northeast-1':
@@ -242,7 +242,7 @@
 														 'secret'	=> $_POST[ 's3secretkey' ],
 														 'region'	=> $_POST[ 's3region' ],
 														 'base_url'	=> $this->get_s3_base_url( $_POST[ 's3region' ], $_POST[ 's3base_url' ]),
-														 'scheme'	=> 'https',
+														 'scheme'	=> 'http',  // Was 'https',
 														 'ssl.certificate_authority' => BackWPup::get_plugin_data( 'cacert' ) ) );
 				// set bucket creation region
 				if ( $_POST[ 's3region' ] === 'google-storage' ) {

I will concede that this is not a great idea but I am stuck until I get time to migrate my site to an newer server within the same hosting company.

Is there a way to skip the SSL check without changing the file?
Can I set curl options via php.ini?

https://wordpress.org/plugins/backwpup/