Fix build with non-OpenSSL SSL-enabled backends
Fix build with non-OpenSSL SSL-enabled backends

Qt 5.4 introduced the ability to split out the OpenSSL-specific parts
of SSL, so allow users of this configuration to still build the SSL
server.

Change-Id: I03e446c1c0fa4062afe16e58d1b7a80373da12a6
Reviewed-by: Maurice Kalinowski <4a4c8e0f704a5a30e402fd2bb0da8c84a569e2df@digia.com>

pixty/qtwebsockets,pixty/qtwebsockets