Fix trace.py for library filenames containing colons (iovisor#1252)

`trace.py` parses a probe using the colon as a separator.  As a result, it
fails to create a uprobe for binary/library with a filename containing colons.

This diff fixes that issue with `trace.py`.  It requires a kernel with
https://lkml.org/lkml/2017/1/13/585 merged to work properly, otherwise
`trace.py` still fails for create uprobes.

tools/trace.py

@@ -136,15 +136,15 @@ def _parse_spec(self, spec):
  self.library = "" # kernel
  self.function = "" # from TRACEPOINT_PROBE
  elif self.probe_type == "u":
- self.library = parts[1]
- self.usdt_name = parts[2]
+ self.library = ':'.join(parts[1:-1])
+ self.usdt_name = parts[-1]
  self.function = "" # no function, just address
  # We will discover the USDT provider by matching on
  # the USDT name in the specified library
  self._find_usdt_probe()
  else:
- self.library = parts[1]
- self.function = parts[2]
+ self.library = ':'.join(parts[1:-1])
+ self.function = parts[-1]
 
  def _find_usdt_probe(self):
  target = Probe.pid if Probe.pid and Probe.pid != -1 \