dotnet-install.sh: line 1172: http_code: unbound variable

[akoeplinger]

Happened in https://dev.azure.com/dnceng-public/public/_build/results?buildId=1103973&view=logs&j=269f5d52-982b-5966-fca9-1b2b0a5feb6e&t=5635d2d0-8bb9-5f32-5791-31370b616264&l=3746 / dotnet/runtime#118278

From looking at the code this can happen if the timeout case occurs because then we don't set the http_code variable:

install-scripts/src/dotnet-install.sh

Lines 1216 to 1226 in 8bbdfaf

	# Check for curl timeout codes
	if [[ $curl_exit_code == 7 || $curl_exit_code == 28 ]]; then
	download_error_msg+=" Failed to reach the server: connection timeout."
	else
	local disable_feed_credential=false
	local response=$(get_http_header_curl $remote_path $disable_feed_credential)
	http_code=$( echo "$response" | awk '/^HTTP/{print $2}' | tail -1 )
	if [[ ! -z $http_code && $http_code != 2* ]]; then
	download_error_msg+=" Returned HTTP status code: $http_code."
	fi
	fi

[ellahathaway]

Reopening this issue until the fix in #630 rolls out.