TEST: Modified from_file_map() in brikhead.py

`brikhead.AFNIImage.from_file_map()` was needlessly opening the 'image' file
before passing it to ImageArrayProxy, potentially causing issues seen on
AppVeyor with mmaps. This commit modifies the call to be more in line with how
this is handled in analyze.py.

Author: rmarkello

nibabel/brikhead.py

@@ -207,9 +207,10 @@ def __init__(self, file_like, header, mmap=True, keep_file_open=None):
             ``'auto'``, and the optional ``indexed_gzip`` dependency is
             present, a single file handle is created and persisted. If
             ``indexed_gzip`` is not available, behaviour is the same as if
-            ``keep_file_open is False``. If ``file_like`` is an open file
-            handle, this setting has no effect. The default value (``None``)
-            will result in the value of ``KEEP_FILE_OPEN_DEFAULT`` being used.
+            ``keep_file_open is False``. If ``file_like`` refers to an open
+            file handle, this setting has no effect. The default value
+            (``None``) will result in the value of
+            ``nibabel.arrayproxy.KEEP_FILE_OPEN_DEFAULT` being used.
         """
         super(AFNIArrayProxy, self).__init__(file_like,
                                              header,
@@ -437,11 +438,11 @@ def from_file_map(klass, file_map, mmap=True):
             read array from file.
         """
         with file_map['header'].get_prepare_fileobj('rt') as hdr_fobj:
-            hdr = klass.header_class.from_fileobj(
-                hdr_fobj)
-        brik_fobj = file_map['image'].get_prepare_fileobj()
-        data = klass.ImageArrayProxy(brik_fobj, hdr,
-                                     mmap=mmap)
+            hdr = klass.header_class.from_fileobj(hdr_fobj)
+        imgf = file_map['image'].fileobj
+        if imgf is None:
+            imgf = file_map['image'].filename
+        data = klass.ImageArrayProxy(imgf, hdr.copy(), mmap=mmap)
         return klass(data, hdr.get_affine(), header=hdr, extra=None,
                      file_map=file_map)