Fix pycuda import to remove tests error.

theano/misc/pycuda_init.py

@@ -41,15 +41,21 @@ if (not hasattr(theano.sandbox, 'cuda') or
             import pycuda.autoinit
             pycuda_available = True
 else:
+    try:
         import pycuda.driver
+        pycuda_available = True
+    except ImportError:
+        pass
+    if pycuda_available:
         if hasattr(pycuda.driver.Context, "attach"):
             pycuda.driver.Context.attach()
         else:
-        # Now we always import this file when we call theano.sandbox.cuda.use
-        # So this should not happen normally.
+            # Now we always import this file when we call
+            # theano.sandbox.cuda.use. So this should not happen
+            # normally.
             # TODO: make this an error.
-        warnings.warn("For some unknow reason, theano.misc.pycuda_init was not"
-                      " imported before Theano initialized the GPU and"
+            warnings.warn("For some unknow reason, theano.misc.pycuda_init was"
+                          " not imported before Theano initialized the GPU and"
                           " your PyCUDA version is 2011.2.2 or earlier."
                           " To fix the problem, import theano.misc.pycuda_init"
                           " manually before using/initializing the GPU, use the"