I have tried to deploy the app in a Samsung tablet (SM-T231 if it matters) running android 4.4.2.
I/GooglePlugin(16037): Building Google options
I/GooglePlugin(16037): Building GoogleApiClient
I/GooglePlugin(16037): GoogleApiClient built
I/GooglePlugin(16037): Trying to Log in!
E/Parcel ( 1181): Class not found when unmarshalling: com.google.android.gms.auth.api.signin.internal.SignInConfiguration
E/Parcel ( 1181): java.lang.ClassNotFoundException: com.google.android.gms.auth.api.signin.internal.SignInConfiguration
E/Parcel ( 1181): at java.lang.Class.classForName(Native Method)
E/Parcel ( 1181): at java.lang.Class.forName(Class.java:251)
E/Parcel ( 1181): at java.lang.Class.forName(Class.java:216)
E/Parcel ( 1181): at android.os.Parcel.readParcelableCreator(Parcel.java:2140)
E/Parcel ( 1181): at android.os.Parcel.readParcelable(Parcel.java:2104)
E/Parcel ( 1181): at android.os.Parcel.readValue(Parcel.java:2020)
E/Parcel ( 1181): at android.os.Parcel.readArrayMapInternal(Parcel.java:2321)
E/Parcel ( 1181): at android.os.Bundle.unparcel(Bundle.java:249)
E/Parcel ( 1181): at android.os.Bundle.getString(Bundle.java:1118)
E/Parcel ( 1181): at android.content.Intent.getStringExtra(Intent.java:5145)
E/Parcel ( 1181): at com.android.server.am.ActivityStackSupervisor.startActivityLocked(ActivityStackSupervisor.java:1466)
E/Parcel ( 1181): at com.android.server.am.ActivityStackSupervisor.startActivityMayWait(ActivityStackSupervisor.java:1061)
E/Parcel ( 1181): at com.android.server.am.ActivityManagerService.startActivityAsUser(ActivityManagerService.java:4067)
E/Parcel ( 1181): at com.android.server.am.ActivityManagerService.startActivity(ActivityManagerService.java:3965)
E/Parcel ( 1181): at android.app.ActivityManagerNative.onTransact(ActivityManagerNative.java:159)
E/Parcel ( 1181): at com.android.server.am.ActivityManagerService.onTransact(ActivityManagerService.java:2646)
E/Parcel ( 1181): at android.os.Binder.execTransact(Binder.java:404)
E/Parcel ( 1181): at dalvik.system.NativeStart.run(Native Method)
E/Parcel ( 1181): Caused by: java.lang.NoClassDefFoundError: com/google/android/gms/auth/api/signin/internal/SignInConfiguration
E/Parcel ( 1181): ... 18 more
E/Parcel ( 1181): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.google.android.gms.auth.api.signin.internal.SignInConfiguration" on path: DexPathList[[directory "."],nativeLibraryDirectories=[/vendor/lib, /system/lib]]
E/Parcel ( 1181): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
E/Parcel ( 1181): at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
E/Parcel ( 1181): at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
E/Parcel ( 1181): ... 18 more