sparsify, v2v: use Common_utils.absolute_path

Use the common function for ensuring a path is absolute; it should not
change the behaviour at all.

sparsify/cmdline.ml

@@ -142,11 +142,7 @@ read the man page virt-sparsify(1).
       (* The input disk must be an absolute path, so we can store the name
        * in the overlay disk.
        *)
-      let indisk =
-        if not (Filename.is_relative indisk) then
-          indisk
-        else
-          Sys.getcwd () // indisk in
+      let indisk = absolute_path indisk in
 
       (* Check the output is not a char special (RHBZ#1056290). *)
       if is_char_device outdisk then

v2v/input_disk.ml

@@ -63,9 +63,7 @@ class input_disk input_format disk = object
       error (f_"-i disk: invalid input filename (%s)") disk;
 
     (* Get the absolute path to the disk file. *)
-    let disk_absolute =
-      if not (Filename.is_relative disk) then disk
-      else Sys.getcwd () // disk in
+    let disk_absolute = absolute_path disk in
 
     (* The rest of virt-v2v doesn't actually work unless we detect
      * the format of the input, so:

v2v/input_ova.ml

@@ -100,9 +100,7 @@ object
       ) in
 
     (* Exploded path must be absolute (RHBZ#1155121). *)
-    let exploded =
-      if not (Filename.is_relative exploded) then exploded
-      else Sys.getcwd () // exploded in
+    let exploded = absolute_path exploded in
 
     (* Find files in [dir] ending with [ext]. *)
     let find_files dir ext =