Fix unitialized value

[ghost]

#692 adds a new parameter. However not specifying its value will give the following message in t/test01.t (see Travis output from the PR) :

Use of uninitialized value $val in numeric gt (>) at /home/travis/build/zonemaster/zonemaster-backend/build_dir/lib/Zonemaster/Backend/Config.pm line 331.

This PR passes the default value (set to 600 seconds = 10 minutes) to the val() call if the the parameter age_reuse_previous_test does not exist.

[matsduf]

@PNAX, could you add how to test this PR at release testing?

[ghost]

This PR on its own is just fixing the code of #692 so that we don't call an uninitialized value.

Before, make test give an ouptut like the following :

PERL_DL_NONLAZY=1 "/usr/bin/perl" "-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef *Test::Harness::Switches; test_harness(0, 'inc', 'blib/lib', 'blib/arch')" t/*.t                                        
t/test01.t ................ 1/? Use of uninitialized value $val in numeric gt (>) at /zonemaster/zonemaster-backend/blib/lib/Zonemaster/Backend/Config.pm line 331.                                     
t/test01.t ................ 11/? Use of uninitialized value $val in numeric gt (>) at /zonemaster/zonemaster-backend/blib/lib/Zonemaster/Backend/Config.pm line 331.                                    
t/test01.t ................ ok
t/test_validate_syntax.t .. ok
All tests successful.

With this PR, the output should be as (no more complaining message about uninitialized value) :

PERL_DL_NONLAZY=1 "/usr/bin/perl" "-MExtUtils::Command::MM" "-MTest::Harness" "-e" "undef *Test::Harness::Switches; test_harness(0, 'inc', 'blib/lib', 'blib/arch')" t/*.t                                        
t/test01.t ................ ok
t/test_validate_syntax.t .. ok
All tests successful.

By the way I don't know why the tests are passing even though there is this uninitialized variable.

[matsduf]

By the way I don't know why the tests are passing even though there is this uninitialized variable.

Because it is just a warning and the undefined value is handled as if zero.

[matsduf]

@PNAX, please merge.

[mattias-p]

There's a unit test for this now:

zonemaster-backend/t/config.t

Line 80 in 4d4392d

is $config->ZONEMASTER_age_reuse_previous_test, 600, 'default: ZONEMASTER.age_reuse_previous_test';