Refactor the while loop so it doesn't use a subshell anymore. Also use
"read -r" to prevent backslash escaping.
```
In testssl.sh line 1193:
app_banners="$app_bannersline"
^-- SC2030: Modification of app_banners is local (to subshell caused by pipeline).
In testssl.sh line 1195:
fileout "app_banner" "WARN" "Application Banners found: $app_banners"
^-- SC2031: app_banners was modified in a subshell. That change might be lost.
```
Found by ShellCheck.
This commit fixes the following two instances of referenced but not assigned
variables:
```
In testssl.sh line 1159:
rp_banners="$rp_bannersline"
^-- SC2154: rp_bannersline is referenced but not assigned.
In testssl.sh line 1193:
app_banners="$app_bannersline"
^-- SC2154: app_bannersline is referenced but not assigned.
```
Found by ShellCheck.
Fix referenced but not assigned variable 'sign_algo'.
In testssl.sh line 4309:
fileout "${json_prefix}algorithm" "DEBUG" "Signature Algorithm: $sign_algo"
^-- SC2154: sign_algo is referenced but not assigned.
Found by ShellCheck.
Two instances of referenced but not assigned variables ('req' instead of
'ret').
In testssl.sh line 4130:
if [[ $req -eq 0 ]]; then
^-- SC2154: req is referenced but not assigned.
Found by ShellCheck.
Karsten Weiss