signv4: remove duplicate assignment

[l2dy]

fluent-bit/src/flb_signv4.c

Lines 970 to 984 in 4b9ac8c

	header_value = tmp;
	len = flb_sds_len(header_value);
	ret = flb_http_add_header(c, "Authorization", 13, header_value, len);
	if (ret == -1) {
	flb_error("[signv4] could not add authorization header");
	flb_sds_destroy(header_value);
	return NULL;
	}
	header_value = tmp;
	/* Return the composed final header for testing if required */
	return header_value;
	}

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Fluent Bit is licensed under Apache 2.0, by submitting this pull request I understand that this code will be released under the terms of that license.

[edsiper]

thanks