fix restart after a crash (it would not restart if there was a stale pid

file from the previous execution)

app/src/main/java/org/galexander/sshd/SimpleSSHDService.java

@@ -195,7 +195,7 @@ public class SimpleSSHDService extends Service {
 				synchronized (lock) {
 					stop_sshd();
 					sshd_pid = pid;
-					sshd_when = System.currentTimeMillis();
+					sshd_when = 0;
 					sshd_duration = 0;
 				}
 			}

doc/index.html

@@ -184,6 +184,7 @@ regular <tt>rsa</tt> key for greatest compatibility.
 <h2>Change Log</h2>
 
 <ul>
+<li> <b>2019/08/11 Version 21:</b> Fix restarting after a crash.
 <li> <b>2019/06/16 Version 20:</b> Update SDK.  Support x86_64, arm64.
 Fix finding support libraries.  Fix colors again.  Fix start-on-boot on
 new Android.  Update to dropbear 2019.78.