convert: separate trunk detection from branch layout detection
In some subversion repositories, trunk is present but no branches
are used. The current code is assuming that both trunk and branches
must exist before adding trunk's head to the heads list.
It's just better to separate the branch layout stuff from the trunk one.
syntax: glob
*.elc
*.orig
*.rej
*~
*.mergebackup
*.o
*.so
*.pyc
*.swp
*.prof
tests/.coverage*
tests/annotated
tests/*.err
build
contrib/hgsh/hgsh
dist
doc/*.[0-9]
doc/*.[0-9].gendoc.txt
doc/*.[0-9].{x,ht}ml
MANIFEST
patches
mercurial/__version__.py
Output/Mercurial-*.exe
.DS_Store
tags
cscope.*
syntax: regexp
^\.pc/