Fix MSBuild error

Author: jpobst

src/Xamarin.Android.Build.Tasks/MSBuild/Xamarin/Android/Xamarin.Android.Bindings.Maven.targets

@@ -15,7 +15,7 @@ This file contains MSBuild targets used to enable @(AndroidMavenLibrary) support
     <!-- Maven cache directory location -->
     <MavenCacheDirectory Condition="$([MSBuild]::IsOSPlatform('Windows')) and '$(MavenCacheDirectory)'==''">$(LocalAppData)\dotnet-android\MavenCacheDirectory\</MavenCacheDirectory>
     <MavenCacheDirectory Condition="$([MSBuild]::IsOSPlatform('OSX')) and '$(MavenCacheDirectory)'==''">$(HOME)/Library/Caches/dotnet-android/MavenCacheDirectory/</MavenCacheDirectory>
-    <MavenCacheDirectory Condition="$'$(MavenCacheDirectory)'==''">$(HOME)/.cache/dotnet-android/MavenCacheDirectory/</MavenCacheDirectory>
+    <MavenCacheDirectory Condition="'$(MavenCacheDirectory)'==''">$(HOME)/.cache/dotnet-android/MavenCacheDirectory/</MavenCacheDirectory>
     <MavenCacheDirectory>$([MSBuild]::EnsureTrailingSlash('$(MavenCacheDirectory)')</MavenCacheDirectory>
   </PropertyGroup>