Merge branch 'jc/receive-verify'

* jc/receive-verify:
receive-pack: check connectivity before concluding "git push"
check_everything_connected(): libify
check_everything_connected(): refactor to use an iterator
fetch: verify we have everything we need before updating our ref

Conflicts:
builtin/fetch.c

diff --cc Makefile
index 68201dea7838bd12b8be7432f9fe4366033bda1a,23d765892470d0f65c3e55cef556b0d95b00c6f8..741aac424f11877e1fea39647ef39ba73de46639
--- 1/Makefile
--- 2/Makefile
+++ b/Makefile
@@@ -593,9 -586,9 +594,10 @@@ LIB_OBJS += cache-tree.
  LIB_OBJS += color.o
  LIB_OBJS += combine-diff.o
  LIB_OBJS += commit.o
 +LIB_OBJS += compat/obstack.o
  LIB_OBJS += config.o
  LIB_OBJS += connect.o
+ LIB_OBJS += connected.o
  LIB_OBJS += convert.o
  LIB_OBJS += copy.o
  LIB_OBJS += csum-file.o

diff --cc builtin/fetch.c
Simple merge

diff --cc builtin/receive-pack.c
Simple merge