Revert of Android: Update docs to say Java 8 is required

docs/android_build_instructions.md

Index: docs/android_build_instructions.md
diff --git a/docs/android_build_instructions.md b/docs/android_build_instructions.md
index a0f95414acb5df38ca74632d0a9df77c298a38a9..be30dfa87bf3affc3384658c6e6aeb725eed3b0d 100644
--- a/docs/android_build_instructions.md
+++ b/docs/android_build_instructions.md
@@ -111,6 +111,19 @@
 keys](https://www.chromium.org/developers/how-tos/api-keys) if you want your
 build to talk to some Google services, but this is not necessary for most
 development and testing purposes.
+
+### Configure the JDK
+
+Make also sure that OpenJDK 1.7 is selected as default:
+
+```shell
+$ sudo update-alternatives --config javac
+$ sudo update-alternatives --config java
+$ sudo update-alternatives --config javaws
+$ sudo update-alternatives --config javap
+$ sudo update-alternatives --config jar
+$ sudo update-alternatives --config jarsigner
+```
 
 ## Setting up the build