Merge branch 'jh/strbuf-read-use-read-in-full' into maint

strbuf_read() used to have one extra iteration (and an unnecessary
strbuf_grow() of 8kB), which was eliminated.

* jh/strbuf-read-use-read-in-full:
strbuf_read(): skip unnecessary strbuf_grow() at eof

diff --cc strbuf.c
Simple merge