Merge branch 'maint'

* maint:
remote: create fetch config lines with '+'
push: allow unqualified dest refspecs to DWIM
doc/git-gc: add a note about what is collected
t5516: remove ambiguity test (1)
Linked glossary from cvs-migration page
write-tree: properly detect failure to write tree objects

diff --cc builtin-remote.c
Simple merge