hash-lookup: rename from sha1-lookup

Change all remnants of "sha1" in hash-lookup.c and .h and rename them to
reflect that we're not just able to handle SHA-1 these days.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/oid-array.c b/oid-array.c
index fb4c3dd..889b311 100644
--- a/oid-array.c
+++ b/oid-array.c
@@ -1,6 +1,6 @@
 #include "cache.h"
 #include "oid-array.h"
-#include "sha1-lookup.h"
+#include "hash-lookup.h"
 
 void oid_array_append(struct oid_array *array, const struct object_id *oid)
 {