CLEANUP: srv: fix comment for pool-max-conn

Adjust comment for the unlimited value of pool-max-conn which is -1.
diff --git a/src/server.c b/src/server.c
index 9508209..9561965 100644
--- a/src/server.c
+++ b/src/server.c
@@ -1262,7 +1262,7 @@
 	{ "non-stick",           srv_parse_non_stick,           0,  1 }, /* Disable stick-table persistence */
 	{ "observe",             srv_parse_observe,             1,  1 }, /* Enables health adjusting based on observing communication with the server */
 	{ "pool-low-conn",       srv_parse_pool_low_conn,       1,  1 }, /* Set the min number of orphan idle connecbefore being allowed to pick from other threads */
-	{ "pool-max-conn",       srv_parse_pool_max_conn,       1,  1 }, /* Set the max number of orphan idle connections, 0 means unlimited */
+	{ "pool-max-conn",       srv_parse_pool_max_conn,       1,  1 }, /* Set the max number of orphan idle connections, -1 means unlimited */
 	{ "pool-purge-delay",    srv_parse_pool_purge_delay,    1,  1 }, /* Set the time before we destroy orphan idle connections, defaults to 1s */
 	{ "proto",               srv_parse_proto,               1,  1 }, /* Set the proto to use for all outgoing connections */
 	{ "proxy-v2-options",    srv_parse_proxy_v2_options,    1,  1 }, /* options for send-proxy-v2 */