Installing additional certificates for SVN fails

[ppxl]

With the implementation of additional SSL certificates in issue #94 and PR #95 the sourcing of the Java base image function existAdditionalCertificates() does not exist. The bash script fails silently because the function is called within a if.

The result is that Subversion does not receive additional certificates and may decline custom SSL certificates as invalid.

Affected versions: v2.289.2-2 and higher