Revert "Drop support for Android 5.x"

This reverts commit 443024cebb. Guess I'll do this a bit later so scb can get another major update first.

April Fools or whatever.

app/src/main/java/eu/kanade/tachiyomi/network/CloudflareInterceptor.kt

@@ -2,6 +2,7 @@ package eu.kanade.tachiyomi.network
 
 import android.annotation.SuppressLint
 import android.content.Context
+import android.os.Build
 import android.os.Handler
 import android.os.Looper
 import android.webkit.WebSettings
@@ -113,7 +114,10 @@ class CloudflareInterceptor(private val context: Context) : Interceptor {
                         latch.countDown()
                     }
 
-                    if (url == origRequestUrl && !challengeFound) {
+                    // HTTP error codes are only received since M
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M &&
+                        url == origRequestUrl && !challengeFound
+                    ) {
                         // The first request didn't return the challenge, abort.
                         latch.countDown()
                     }