Remove .idea files from samples

Change-Id: I0793e84b9c0e731404b92f0c1ee4b412143ae715
diff --git a/build.gradle b/build.gradle
index d643cd0..e1dc109 100644
--- a/build.gradle
+++ b/build.gradle
@@ -134,6 +134,7 @@
         exclude "local.properties"
         exclude "template-params.xml"
         exclude "*.iml"
+        exclude "**/.idea"
         exclude "**/build"
         exclude "**/proguard-project.txt"
         exclude "${samplegen.targetSampleModule()}/**/README*.txt"