modem-helpers: Don't leak str when parsing cscb response

We currently overwrite the value without freeing it.

Fixes: d8135be6e ("modem-helpers: Add helpers to parse channel lists")

Signed-off-by: Guido Günther <agx@sigxcpu.org>

src/mm-modem-helpers.c

@@ -3162,6 +3162,7 @@ mm_3gpp_parse_cscb_response (const char *response, GError **error)
         goto out;
     }
 
+    g_free (str);
     str = g_match_info_fetch (match_info, 2);
     intervals = g_strsplit (str, ",", -1);
     for (i = 0; intervals[i]; i++) {