fileops: rename to "futils.h" to match function signatures

Our file utils functions all have a "futils" prefix, e.g.
`git_futils_touch`. One would thus naturally guess that their
definitions and implementation would live in files "futils.h" and
"futils.c", respectively, but in fact they live in "fileops.h".

Rename the files to match expectations.

Author: pks-t

fuzzers/standalone_driver.c

@@ -8,7 +8,7 @@
 #include <stdio.h>
 
 #include "git2.h"
-#include "fileops.h"
+#include "futils.h"
 #include "path.h"
 
 extern int LLVMFuzzerTestOneInput(const unsigned char *data, size_t size);

src/apply.c

@@ -18,7 +18,7 @@
 #include "git2/repository.h"
 #include "array.h"
 #include "patch.h"
-#include "fileops.h"
+#include "futils.h"
 #include "delta.h"
 #include "zstream.h"
 #include "reader.h"

src/attr_file.h

@@ -14,7 +14,7 @@
 #include "vector.h"
 #include "pool.h"
 #include "buffer.h"
-#include "fileops.h"
+#include "futils.h"
 
 #define GIT_ATTR_FILE			".gitattributes"
 #define GIT_ATTR_FILE_INREPO	"attributes"

src/blob.h

@@ -12,7 +12,7 @@
 #include "git2/blob.h"
 #include "repository.h"
 #include "odb.h"
-#include "fileops.h"
+#include "futils.h"
 
 struct git_blob {
 	git_object object;

src/clone.c

@@ -19,7 +19,7 @@
 #include "git2/tree.h"
 
 #include "remote.h"
-#include "fileops.h"
+#include "futils.h"
 #include "refs.h"
 #include "path.h"
 #include "repository.h"

src/config_cache.c

@@ -7,7 +7,7 @@
 
 #include "common.h"
 
-#include "fileops.h"
+#include "futils.h"
 #include "repository.h"
 #include "config.h"
 #include "git2/config.h"

src/config_parse.h

@@ -10,7 +10,7 @@
 #include "common.h"
 
 #include "array.h"
-#include "fileops.h"
+#include "futils.h"
 #include "oid.h"
 #include "parse.h"
 

src/crlf.c

@@ -12,7 +12,7 @@
 #include "git2/index.h"
 #include "git2/sys/filter.h"
 
-#include "fileops.h"
+#include "futils.h"
 #include "hash.h"
 #include "filter.h"
 #include "buf_text.h"

src/diff_file.c

@@ -12,7 +12,7 @@
 #include "diff.h"
 #include "diff_generate.h"
 #include "odb.h"
-#include "fileops.h"
+#include "futils.h"
 #include "filter.h"
 
 #define DIFF_MAX_FILESIZE 0x20000000

src/diff_generate.c

@@ -9,7 +9,7 @@
 
 #include "diff.h"
 #include "patch_generate.h"
-#include "fileops.h"
+#include "futils.h"
 #include "config.h"
 #include "attr_file.h"
 #include "filter.h"