forgot to move test classpath out of root project

OpenKeychain/build.gradle

@@ -1,5 +1,4 @@
 apply plugin: 'android'
-apply plugin: 'robolectric'
 
 dependencies {
     // NOTE: Always use fixed version codes not dynamic ones, e.g. 0.7.3 instead of 0.7.+, see README for more information