print msg.command in human-readable format

to print msg.command as some odd decimal number is just not helping in debugging;
instead print msg.command as a string

Change-Id: Id1ec770c20c86b8bdae40a0262bf4b63c0213b0a
diff --git a/adb/adb.c b/adb/adb.c
index 95dc001..ee78688 100644
--- a/adb/adb.c
+++ b/adb/adb.c
@@ -302,8 +302,10 @@
 {
     asocket *s;
 
-    D("handle_packet() %d\n", p->msg.command);
-
+    D("handle_packet() %c%c%c%c\n", ((char*) (&(p->msg.command)))[0],
+            ((char*) (&(p->msg.command)))[1],
+            ((char*) (&(p->msg.command)))[2],
+            ((char*) (&(p->msg.command)))[3]);
     print_packet("recv", p);
 
     switch(p->msg.command){