Merge branch 'rs/misc-cppcheck-fixes'

Various small fixes.

* rs/misc-cppcheck-fixes:
server-info: avoid calling fclose(3) twice in update_info_file()
files_for_each_reflog_ent_reverse(): close stream and free strbuf on error
am: close stream on error, but not stdin

diff --cc builtin/am.c
Simple merge

diff --cc refs/files-backend.c
Simple merge