BUG/MINOR: config: fix leak on proxy.conn_src.bind_hdr_name

Leak for parsing of option usesrc of the source keyword.

This can be backported to 1.8.

(cherry picked from commit 69c5c3ab330584f9c53e2cf7c86af371a84f104d)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 7edf20eb55282d86e78fa1c642975b4b8ffcbec4)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 50c1fa2e4c59e097b10ee4d7fab699e8a8a5e73b)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
(cherry picked from commit 837559375bcb35b80eaaf777431e2be6033080ed)
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
diff --git a/src/cfgparse-listen.c b/src/cfgparse-listen.c
index 2ecf951..7f2acf2 100644
--- a/src/cfgparse-listen.c
+++ b/src/cfgparse-listen.c
@@ -3919,6 +3919,7 @@
 
 					curproxy->conn_src.opts &= ~CO_SRC_TPROXY_MASK;
 					curproxy->conn_src.opts |= CO_SRC_TPROXY_DYN;
+					free(curproxy->conn_src.bind_hdr_name);
 					curproxy->conn_src.bind_hdr_name = calloc(1, end - name + 1);
 					curproxy->conn_src.bind_hdr_len = end - name;
 					memcpy(curproxy->conn_src.bind_hdr_name, name, end - name);