Use '-a' operator as 'AND' instead of '&&' in deb/postinst script

[hirakuro]

On installing ganttproject_2.8.3-r2088-1_all.deb, I found an error bellow is shown.

/var/lib/dpkg/info/ganttproject.postinst: 11: [: missing ]

In ganttproject.postinst, an operaotr && is used in [ command, but it should be -a.

[dbarashev]

Hi, thanks for reporting this issue! It seems that -a operator is deprecated, though. The right way of fixing is to close left expression with ] and open right expression with [ (done in my commit above).

[hirakuro]

Thank you very much for your comment and more appropriate fix.
I did not know that -a is deprecated, thanks!