gen-pkcs12-keystore init container fails if the tls secret contains no ca.crt

[smoldenhauer-ish]

gen-pkcs12-keystore init container fails if the tls secret contains no ca.crt

[smoldenhauer-ish]

I will provide a pull request to include the -in ca.crt only if there is a ca.crt file present:

Tested:

    Command:
      sh
      -c
      OPTIONAL_CACRT=$(test -e /var/solr/tls/ca.crt && echo ' -in /var/solr/tls/ca.crt'); openssl pkcs12 -export -in /var/solr/tls/tls.crt $OPTIONAL_CACRT -inkey /var/solr/tls/tls.key -out /var/solr/tls/pkcs12/keystore.p12 -passout pass:${SOLR_SSL_KEY_STORE_PASSWORD}