hello-libs: Add abiFilters to gen-libs module

After updating Android Studio to v3.0.1 (and Gradle plugin to v3.0.1),
I noticed that libhello-libs.so is being built for more architectures
than libgperf.so. Also I noticed that app/build.gradle has abiFilters,
but gen-lib/build.gradle doesn't. This leads to linking errors. That
issue is reported as #450. See [1] for details.

Adding the same abiFilters line to gen-lib/build.gradle fixes the issue.

While at it, remove armeabi architecture from app/build.gradle
abiFilters, as it's deprecated now. See [2] for details.

[1] https://github.com/googlesamples/android-ndk/issues/450
[2] https://developer.android.com/ndk/guides/abis.html

Signed-off-by: Sam Protsenko <joe.skb7@gmail.com>

hello-libs/app/build.gradle

@@ -11,7 +11,7 @@ android {
         versionCode = 1
         versionName = '1.0'
         ndk {
-            abiFilters 'x86', 'x86_64', 'armeabi', 'armeabi-v7a', 'arm64-v8a'
+            abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a'
         }
         externalNativeBuild {
             cmake {

hello-libs/gen-libs/build.gradle

@@ -10,6 +10,9 @@ android {
         versionCode 1
         versionName "1.0"
 
+        ndk {
+            abiFilters 'x86', 'x86_64', 'armeabi-v7a', 'arm64-v8a'
+        }
         externalNativeBuild {
             cmake {
                 arguments '-DANDROID_PLATFORM=android-14',