BUILD: cfgparse-ssl: Remove const from defpx param in keylog parsing function

defpx parameter is const in cfg parsing functions since the 2.4. It is not
const in 2.3 and below. This build issue was introduced by the commit
b32469435c ("BUILD: make tune.ssl.keylog available again").

This patch is 2.3-specific. Thus there is upstream commid ID. And no
backport is needed, except if the commit above is backported.
1 file changed