Redirect stderr to stdout and prevent display error

[vitormattos]

Problem

When the command return any type of error, the error will be displayed in terminal. JSignPdf display a warning every time when is executed without the property file.

Ref: LibreSign/libresign#1144

Output with warning:

FINE Default property file doesn't exists.
FINE Default property file doesn't exists.

Solution

Redirect stderr to stdout because the unique necessary output that we need is the last output row of --version.

As described in this stackoverflow link, work fine in Linux and in proprietary OS that I won't pronounce the name.

https://stackoverflow.com/questions/818255/what-does-21-mean