check-code.py: avoid warning against "reverting subrepo ..." lines
Before this patch, "reverting subrepo subrepo/path" lines in *.t test
files require "(glob)", because such lines are recognized as
"reverting path/to/managed/file" by "check-code.py".
On the other hand, "(glob)" for such "reverting ..." line is
recognized as useless by "runt-tests.py", because subrepo paths shown
in such lines are always normalized by "util.pconvert". And this
causes "no result code from test" warning.
As a preparation for discarding "(glob)" from such lines in subsequent
patch, this patch avoids warning against them, by adding negative
lookahead assertion "(?!subrepo )" to the regexp.