Restore minSdkVersion in manifest

minSdkVersion turned out to be affecting manifest merging. The merger
adds permissions for backward compatibility reasons.

TBR: peconn@chromium.org

Change-Id: I11114eb647763d352608cef5eefa151e315c2623
Reviewed-on: https://chromium-review.googlesource.com/c/custom-tabs-client/+/1617462
Reviewed-by: Pavel Shmakov <pshmakov@chromium.org>
Commit-Queue: Pavel Shmakov <pshmakov@chromium.org>
diff --git a/customtabs/AndroidManifest.xml b/customtabs/AndroidManifest.xml
index 99736b1..a3abf5d 100644
--- a/customtabs/AndroidManifest.xml
+++ b/customtabs/AndroidManifest.xml
@@ -16,5 +16,5 @@
 -->
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           package="android.support.customtabs">
-
+    <uses-sdk android:minSdkVersion="16"/>
 </manifest>
\ No newline at end of file