Fix underflow when leave_function() are unbalanced

include/libssh/priv.h

@@ -238,7 +238,7 @@ typedef struct signature_struct {
 
 struct error_struct {
 /* error handling */
-    int error_code;
+    unsigned int error_code;
     char error_buffer[ERROR_BUFFERLEN];
 };
 

libssh/connect.c

@@ -246,7 +246,6 @@ socket_t ssh_connect_host(SSH_SESSION *session, const char *host,
       ssh_set_error(session, SSH_FATAL, "Connect failed: %s", strerror(errno));
       close(s);
       s = -1;
-      leave_function();
       continue;
     } else {
       /* We are connected */