Fix exit status codes

Using an exit status of -1 everywhere leads to the status being
converted to 255 when output to a calling application. While this does
signify an error it has a reserved meaning for exit status out of range.
Lets use a valid general exit status of 1 instead.

Change-Id: I326701c78985e34c430c258fe31d9e910da10405
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/evdevpp/test/evmon.cpp b/evdevpp/test/evmon.cpp
index 26163a7..526f759 100644
--- a/evdevpp/test/evmon.cpp
+++ b/evdevpp/test/evmon.cpp
@@ -40,7 +40,7 @@
         if ((option == '?') || (option == 'h'))
         {
             usage(argv);
-            exit(-1);
+            exit(1);
         }
 
         auto i = &options[0];
@@ -97,7 +97,7 @@
     ArgumentParser::usage(argv);
     std::cerr << "\n";
     std::cerr << "ERROR: " << err << "\n";
-    exit(-1);
+    exit(1);
 }
 
 } // namespace util