[build] fixes for $(Configuration)=Gendarme

I'm not exactly sure how this was working before:
- Gendarme config had no way to import `JdkInfo.props`
- Thus usage of `$(JavaCPath)` was using an empty string?

Configuration.props

@@ -1,21 +1,26 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <!-- Note: MUST be imported *after* $(Configuration) is set! -->
+  <PropertyGroup>
+    <_Configuration Condition=" '$(Configuration)' != 'Gendarme' ">$(Configuration)</_Configuration>
+    <_Configuration Condition=" '$(Configuration)' == 'Gendarme' ">Debug</_Configuration>
+    <_OutputPath>$(MSBuildThisFileDirectory)bin\Build$(_Configuration)\</_OutputPath>
+  </PropertyGroup>
   <Import
       Project="$(MSBuildThisFileDirectory)Configuration.Override.props"
       Condition="Exists('$(MSBuildThisFileDirectory)Configuration.Override.props')"
   />
   <Import
-      Project="$(MSBuildThisFileDirectory)bin\Build$(Configuration)\JdkInfo.props"
-      Condition="Exists('$(MSBuildThisFileDirectory)bin\Build$(Configuration)\JdkInfo.props')"
+      Project="$(_OutputPath)JdkInfo.props"
+      Condition="Exists('$(_OutputPath)JdkInfo.props')"
   />
   <Import
-      Project="$(MSBuildThisFileDirectory)bin\Build$(Configuration)\MonoInfo.props"
-      Condition="Exists('$(MSBuildThisFileDirectory)bin\Build$(Configuration)\MonoInfo.props')"
+      Project="$(_OutputPath)MonoInfo.props"
+      Condition="Exists('$(_OutputPath)MonoInfo.props')"
   />
   <PropertyGroup>
     <CecilSourceDirectory   Condition=" '$(CecilSourceDirectory)' == '' ">$(MSBuildThisFileDirectory)external\cecil</CecilSourceDirectory>
-    <UtilityOutputFullPath  Condition=" '$(UtilityOutputFullPath)' == '' ">$(MSBuildThisFileDirectory)bin\$(Configuration)\</UtilityOutputFullPath>
+    <UtilityOutputFullPath  Condition=" '$(UtilityOutputFullPath)' == '' ">$(MSBuildThisFileDirectory)bin\$(_Configuration)\</UtilityOutputFullPath>
     <XamarinAndroidToolsDirectory   Condition=" '$(XamarinAndroidToolsDirectory)' == '' ">$(MSBuildThisFileDirectory)external\xamarin-android-tools</XamarinAndroidToolsDirectory>
   </PropertyGroup>
   <PropertyGroup>