A couple of small C++ cleanup PATCHes

[Jason Merrill]

Conversion of default arguments is an implicit conversion, so it should 
use LOOKUP_IMPLICIT.

A recent bug involved cp_parser_abort_tentative_parse failing to abort 
because we had already committed to the tentative parse.  So let's avoid 
that in future.

Tested x86_64-pc-linux-gnu, applied to trunk.
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: convert-tidy.patch
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20110316/6d5fcb79/attachment.ksh>
-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: abort-tent.patch
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20110316/6d5fcb79/attachment-0001.ksh>