BUG/MINOR: ssl: Prevent disk access when using "add ssl crt-list"

BUG/MINOR: ssl: Prevent disk access when using "add ssl crt-list"

If an unknown CA file was first mentioned in an "add ssl crt-list" CLI
command, it would result in a call to X509_STORE_load_locations which
performs a disk access which is forbidden during runtime. The same would
happen if a "ca-verify-file" or "crl-file" was specified. This was due
to the fact that the crt-list file parsing and the crt-list related CLI
commands parsing use the same functions.
The patch simply adds a new parameter to all the ssl_bind parsing
functions so that they know if the call is made during init or by the
CLI, and the ssl_store_load_locations function can then reject any new
cafile_entry creation coming from a CLI call.

It can be backported as far as 2.2.

(cherry picked from commit fb00f31af4ba67c69a12807729514a2bdcd47efa)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>