dm vdo test: Ignore use once warning in TesstCase.pm

Add a no warnings 'once' line into TestCase.pm so that we ignore
that issue and it will no longer break make jenkins.

Signed-off-by: Bruce Johnston <bjohnsto@redhat.com>

Author: bjohnsto

perl/Permabit/Testcase.pm

@@ -119,6 +119,9 @@ my $GET_CONSOLE_LOG_CMD
 
 my $log = Log::Log4perl->get_logger(__PACKAGE__);
 
+# Avoid the "used only once" warning which causes failures in 'make jenkins'
+no warnings 'once';
+
 ##
 # @paramList{new}
 our %PROPERTIES