c-icap: update to 0.5.5

c-icap-0.5.5 changes
- c-icap may crash with a SIGBUS while using mmap to map files to memory.
- Fix multiple brotli decoding bugs
- c-icap-client does not send the ";ieof" preview termination sequence when sends zero sized files

c-icap-0.5.4 changes
- Bug fix: IPv6 address can not be used on Port configuration parameter
- Mark as deprecated the tls-method TlsPort option
- Bug fix: c-icap fails to decompress zero-sized files compressed with brotli

c-icap-0.5.2 changes
- Document the forceUnload=off option for Service/Module configuration parameter
- Bug fix: c-icap crashes when converting ci_simple_file_t to a memory object
- ci_headers_value* functions should remove spaces at the beginning of the returned value

c-icap-0.5.1 changes
The 0.5.1 release has the following new major features :
* TLS/SSL support. This feature sponsored by Ergon Informatik AG.
* A non-blocking ICAP client API. This feature sponsored by Ergon Informatik AG.
* Allow 204 response on preview handler even if the ICAP client does not support preview.
* New API functions.

Major bugs fixed:
* c-icap crashes on shutdown or on reconfigure, because of unloaded c++ dynamic libraries. The new release accepts the forceUnload=off parameter to Module and Service configuration parameters to force c-icap to not actually unload dynamic libraries on reconfigure, or shutdown.

New configuration parameters:
* FakeAllow204
* TlsPort
* TlsPassphrase

(sborrill)