Changed logging in unit tests to filter out things we don't need to see

src/Umbraco.Tests/unit-test-log4net.config

@@ -5,6 +5,18 @@
     <appender-ref ref="ConsoleAppender" />
   </root>
 
+  <logger name="Umbraco.Core.PluginManager">
+    <level value="WARN" />
+  </logger>
+
+  <logger name="Umbraco.Core.Persistence.Database">
+    <level value="WARN" />
+  </logger>
+
+  <logger name="Umbraco.Core.Persistence.Migrations.Initial.BaseDataCreation">
+    <level value="WARN" />
+  </logger>  
+
   <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender" >
     <target value="Console.Out" />
     <layout type="log4net.Layout.PatternLayout">