MEDIUM: sample change the prototype of sample-fetches and converters functions

This patch removes the structs "session", "stream" and "proxy" from
the sample-fetches and converters function prototypes.

This permits to remove some weight in the prototype call.
diff --git a/src/frontend.c b/src/frontend.c
index e8531e9..001b74d 100644
--- a/src/frontend.c
+++ b/src/frontend.c
@@ -159,12 +159,12 @@
 
 /* set temp integer to the id of the frontend */
 static int
-smp_fetch_fe_id(struct proxy *px, struct session *sess, struct stream *strm, unsigned int opt,
-                const struct arg *args, struct sample *smp, const char *kw, void *private)
+smp_fetch_fe_id(unsigned int opt, const struct arg *args, struct sample *smp,
+                const char *kw, void *private)
 {
 	smp->flags = SMP_F_VOL_SESS;
 	smp->type = SMP_T_UINT;
-	smp->data.uint = sess->fe->uuid;
+	smp->data.uint = smp->sess->fe->uuid;
 	return 1;
 }
 
@@ -173,8 +173,8 @@
  * an undefined behaviour.
  */
 static int
-smp_fetch_fe_sess_rate(struct proxy *px, struct session *sess, struct stream *strm, unsigned int opt,
-                       const struct arg *args, struct sample *smp, const char *kw, void *private)
+smp_fetch_fe_sess_rate(unsigned int opt, const struct arg *args, struct sample *smp,
+                       const char *kw, void *private)
 {
 	smp->flags = SMP_F_VOL_TEST;
 	smp->type = SMP_T_UINT;
@@ -187,8 +187,8 @@
  * an undefined behaviour.
  */
 static int
-smp_fetch_fe_conn(struct proxy *px, struct session *sess, struct stream *strm, unsigned int opt,
-                  const struct arg *args, struct sample *smp, const char *kw, void *private)
+smp_fetch_fe_conn(unsigned int opt, const struct arg *args, struct sample *smp,
+                  const char *kw, void *private)
 {
 	smp->flags = SMP_F_VOL_TEST;
 	smp->type = SMP_T_UINT;