Avoid inheriting from Exporter in Perl modules

Just import the import function from Exporter instead of inheriting
from it. This works reliably with Perl 5.12 or later.

tests/tap/perl/Test/RRA.pm

@@ -12,10 +12,10 @@ package Test::RRA v11.0.0;
 
 use 5.012;
 use autodie;
-use base qw(Exporter);
 use warnings;
 
 use Carp qw(croak);
+use Exporter qw(import);
 use File::Temp;
 
 # Abort if Test::More was loaded before Test::RRA to be sure that we get the

tests/tap/perl/Test/RRA/Config.pm

@@ -10,9 +10,9 @@
 package Test::RRA::Config v11.0.0;
 
 use 5.012;
-use base qw(Exporter);
 use warnings;
 
+use Exporter qw(import);
 use Test::More;
 
 # Exports.

tests/tap/perl/Test/RRA/ModuleVersion.pm

@@ -10,9 +10,9 @@ package Test::RRA::ModuleVersion v11.0.0;
 
 use 5.012;
 use autodie;
-use base qw(Exporter);
 use warnings;
 
+use Exporter qw(import);
 use File::Find qw(find);
 use Test::More;
 use Test::RRA::Config qw(@MODULE_VERSION_IGNORE);