BUILD: xprt-quic: replace ERR_func_error_string() with ERR_peek_error_func()

OpenSSL 3.0 warns that ERR_func_error_string() is deprecated. Using
ERR_peek_error_func() solves it instead, and this function was added to
the compat layer by commit 1effd9aa0 ("MINOR: ssl: Remove call to
ERR_func_error_string with OpenSSLv3").
1 file changed