Add short prompt format for command line options

Change-Id: I9447ddd0c7fb7e1479be5f26bc295059574ed8f9
Reviewed-on: https://weave-review.googlesource.com/1247
Reviewed-by: Vitaly Buka <vitalybuka@google.com>

libweave/examples/ubuntu/main.cc

diff --git a/libweave/examples/ubuntu/main.cc b/libweave/examples/ubuntu/main.cc
index 5b726fc..5c84d9c 100644
--- a/libweave/examples/ubuntu/main.cc
+++ b/libweave/examples/ubuntu/main.cc
@@ -26,9 +26,9 @@
              << "\nOptions:\n"
              << "\t-h,--help                    Show this help message\n"
              << "\t-b,--bootstrapping           Force WiFi bootstrapping\n"
-             << "\t--disable_security           Disable privet security\n"
-             << "\t--registration_ticket=TICKET Register device with the given "
-                "ticket\n";
+             << "\t-d,--disable_security        Disable privet security\n"
+             << "\t--registration_ticket=TICKET Register device with the "
+                                                "given ticket\n";
 }
 
 class CommandHandler {
@@ -127,7 +127,7 @@
       return 0;
     } else if (arg == "-b" || arg == "--bootstrapping") {
       force_bootstrapping = true;
-    } else if (arg == "--disable_security") {
+    } else if (arg == "-d" || arg == "--disable_security") {
       disable_security = true;
     } else if (arg.find("--registration_ticket") != std::string::npos) {
       auto pos = arg.find("=");