Avoid all systemtap reserved words

Over time various systemtap reserved words have been blacklisted
in the trace backend generator. The list is not complete though,
so there is continued risk of problems in the future. Preempt
such problems by specifying the full list of systemtap keywords
listed in its parser as identified here:

  http://sourceware.org/ml/systemtap/2012-q4/msg00157.htmlSigned-off-by: NDaniel P. Berrange <berrange@redhat.com>
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>

scripts/tracetool/backend/dtrace.py

@@ -73,6 +73,15 @@ def d(events):
         '};')
 
 
+# Technically 'self' is not used by systemtap yet, but
+# they recommended we keep it in the reserved list anyway
+RESERVED_WORDS = (
+    'break', 'catch', 'continue', 'delete', 'else', 'for',
+    'foreach', 'function', 'global', 'if', 'in', 'limit',
+    'long', 'next', 'probe', 'return', 'self', 'string',
+    'try', 'while'
+    )
+
 def stap(events):
     for e in events:
         # Define prototype for probe arguments
@@ -87,7 +96,7 @@ def stap(events):
         if len(e.args) > 0:
             for name in e.args.names():
                 # Append underscore to reserved keywords
-                if name in ('limit', 'in', 'next', 'self', 'function'):
+                if name in RESERVED_WORDS:
                     name += '_'
                 out('  %s = $arg%d;' % (name, i))
                 i += 1