Nuke HelpFileVersion and skip empty BuildNumber msbuild param

Author: bahusoid

default.build

@@ -41,7 +41,7 @@
 			<arg value="/p:IncludeSource=&quot;True&quot;" />
 			<arg value="/p:PackageOutputPath=&quot;${path::get-full-path(nuget.nupackages.dir)}&quot;" />
 			<!-- build.counter is not available by default. It needs to be exposed in Team City as system parameter system.build.counter with value %build.counter% -->
-			<arg value="/p:BuildNumber=&quot;${build.counter}&quot;" />
+			<arg value="/p:BuildNumber=&quot;${build.counter}&quot;" unless="${build.counter == ''}" />
 			<arg value="/t:Restore" />
 			<arg value="/t:Rebuild" />
 			<arg value="/v:q" />

doc/NHibernate.shfbproj.template

@@ -23,7 +23,6 @@
     <FeedbackEMailLinkText>nhibernate team</FeedbackEMailLinkText>
     <HelpTitle>NHibernate API Reference</HelpTitle>
     <IndentHtml>False</IndentHtml>
-    <HelpFileVersion>${project.version.numeric}</HelpFileVersion>
     <DocumentationSources>
       <DocumentationSource sourceFile="${root.dir}/src/NHibernate/bin/${build.config}/net461/NHibernate.dll" />
       <DocumentationSource sourceFile="${root.dir}/src/NHibernate/bin/${build.config}/net461/Nhibernate.xml" />