asterisk: fix vulnerabilities associated with "echo -e"
If multiple arguments are allowed to be passed to echo, it is possible to inject newlines using something like '-e aaa\nbbb\nccc" in UCI.
Also fix missing quotation and missing escape_sed
If multiple arguments are allowed to be passed to echo, it is possible to inject newlines using something like '-e aaa\nbbb\nccc" in UCI.
Also fix missing quotation and missing escape_sed