fix bug: change seed range for RandomStreams in Theano (#2865)

* bug fixed, numpy randint only output positive numbers ranging from 1 to 10e6

* Update theano_backend.py

changed style and numpy randint range

* Update theano_backend.py

removed extra spaces

keras/backend/theano_backend.py

@@ -782,7 +782,7 @@ def dropout(x, level, seed=None):
     if level < 0. or level >= 1:
         raise Exception('Dropout level must be in interval [0, 1[.')
     if seed is None:
-        seed = np.random.randint(10e6)
+        seed = np.random.randint(1, 10e6)
     rng = RandomStreams(seed=seed)
     retain_prob = 1. - level
     x *= rng.binomial(x.shape, p=retain_prob, dtype=x.dtype)
@@ -1027,20 +1027,20 @@ def pool3d(x, pool_size, strides=(1, 1, 1), border_mode='valid',
 
 def random_normal(shape, mean=0.0, std=1.0, dtype=_FLOATX, seed=None):
     if seed is None:
-        seed = np.random.randint(10e6)
+        seed = np.random.randint(1, 10e6)
     rng = RandomStreams(seed=seed)
     return rng.normal(size=shape, avg=mean, std=std, dtype=dtype)
 
 
 def random_uniform(shape, low=0.0, high=1.0, dtype=_FLOATX, seed=None):
     if seed is None:
-        seed = np.random.randint(10e6)
+        seed = np.random.randint(1, 10e6)
     rng = RandomStreams(seed=seed)
     return rng.uniform(shape, low=low, high=high, dtype=dtype)
 
 
 def random_binomial(shape, p=0.0, dtype=_FLOATX, seed=None):
     if seed is None:
-        seed = np.random.randint(10e6)
+        seed = np.random.randint(1, 10e6)
     rng = RandomStreams(seed=seed)
     return rng.binomial(shape, p=p, dtype=dtype)