DOC+RF: minor quaternion cleanup

Minor quaternion docstring cleanup and removing an unused code line.

Author: matthew-brett

nibabel/quaternions.py

@@ -330,8 +330,8 @@ def rotate_vector(v, q):
 def nearly_equivalent(q1, q2, rtol=1e-5, atol=1e-8):
     ''' Returns True if `q1` and `q2` give near equivalent transforms
 
-    q1 may be nearly numerically equal to q2, or nearly equal to q2 * -1
-    (becuase a quaternion multiplied by -1 gives the same transform).
+    `q1` may be nearly numerically equal to `q2`, or nearly equal to `q2` * -1
+    (because a quaternion multiplied by -1 gives the same transform).
 
     Parameters
     ----------
@@ -418,7 +418,7 @@ def angle_axis2mat(theta, vector, is_normalized=False):
     Returns
     -------
     mat : array shape (3,3)
-       rotation matrix specified rotation
+       rotation matrix for specified rotation
 
     Notes
     -----

nibabel/tests/test_quaternions.py

@@ -149,7 +149,6 @@ def test_eye():
 
 
 def test_qrotate():
-    vecs = np.eye(3)
     for vec in np.eye(3):
         for M, q in eg_pairs:
             vdash = nq.rotate_vector(vec, q)