Enable tests by default and change check to allowed

Update these settings according to the comments in [1].

[1]: https://gerrit.openbmc.org/c/openbmc/host-error-monitor/+/66987

Signed-off-by: Jason M. Bills <jason.m.bills@linux.intel.com>
Change-Id: I9feed7d3431fcc212fc669c994e2ff60479bc4c4
diff --git a/meson.build b/meson.build
index 5021056..9293f49 100644
--- a/meson.build
+++ b/meson.build
@@ -81,6 +81,6 @@
 
 subdir('service_files')
 
-if get_option('tests').enabled()
+if get_option('tests').allowed()
     subdir('tests')
 endif