lib/model: Limit the number of default hashers on Android (ref #2220)

Like Windows and Mac, Android is also an interactive operating system.
On top of that, it usually runs on much slower hardware than the other
two. Because of that, it makes sense to limit the number of hashes used
by default there too.

Signed-off-by: Tomasz Wilczyński <[email protected]>

lib/model/model.go

@@ -2403,7 +2403,7 @@ func (m *model) numHashers(folder string) int {
 		return folderCfg.Hashers
 	}
 
-	if runtime.GOOS == "windows" || runtime.GOOS == "darwin" {
+	if runtime.GOOS == "windows" || runtime.GOOS == "darwin" || runtime.GOOS == "android" {
 		// Interactive operating systems; don't load the system too heavily by
 		// default.
 		return 1