More nibabel depreaction fixes

fsl/data/atlases.py

@@ -599,7 +599,7 @@ class Atlas(fslimage.Image):
         # Even though all the FSL atlases
         # are in MNI152 space, not all of
         # their sform_codes are correctly set
-        self.nibImage.get_header().set_sform(
+        self.nibImage.header.set_sform(
             None, code=constants.NIFTI_XFORM_MNI_152)
 
         self.desc = atlasDesc

fsl/data/image.py

@@ -1065,7 +1065,7 @@ class Image(Nifti):
             nib.save(self.__nibImage, filename)
             self.__fileobj.close()
             self.__nibImage, self.__fileobj = loadIndexedImageFile(filename)
-            self.header = self.__nibImage.get_header()
+            self.header = self.__nibImage.header
 
             # We have to create a new ImageWrapper
             # instance too, as we have just destroyed