MGASA-2017-0319 Updated libgit2 packages fix security vulnerabilities

Read out-of-bounds in gitoidnfmt CVE-2016-8568. DoS using a null pointer dereference in gitcommitmessage CVE-2016-8569. Insufficient sanitization allows some edge cases in the Git Smart Protocol which can lead to reading outside of a buffer CVE-2016-10128, CVE-2016-10129...