strvec: rename files from argv-array to strvec

This requires updating #include lines across the code-base, but that's
all fairly mechanical, and was done with:

  git ls-files '*.c' '*.h' |
  xargs perl -i -pe 's/argv-array.h/strvec.h/'

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 7016b28..5f18f0e 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -27,7 +27,7 @@
 #include "delta-islands.h"
 #include "reachable.h"
 #include "oid-array.h"
-#include "argv-array.h"
+#include "strvec.h"
 #include "list.h"
 #include "packfile.h"
 #include "object-store.h"