[PATCH] MC: do not try to parse invalid handled directives

[Matheus Almeida]

  Hum... I'm not sure we need this patch.

  I think what is happening here is that some target assembly parsers are not being coherent w.r.t return values from ParseDirective. My understanding is that:
  True should be returned if a target parser 'doesn't care' about a directive and it should be handled by the generic parser;
  False should be returned if a directive was handled by a target parser independently if successfully parsed. Note that the Error routine sets "HadError" as a side effect which means the assembly parser will return an error value if there was a problem parsing a directive.

  I think the problem is that some target assembly parsers are returning "True" and handling target specific directives which isn't entirely correct.

  Regards,
  Matheus

http://llvm-reviews.chandlerc.com/D2410