Don't error out when cpu accelerator doesn't have torch (as default f…

…or whl building) (#6886)

This fixes a bug introduced in #6845, which breaks the `no-torch`
workflow that we require in order to do releases where we do not require
torch to be in the environment when building an sdist. This adds the
same logic to the cpuaccelerator that the cudaaccelerator had where we
don't require torch to be installed to build the whl.

.github/workflows/no-torch.yml

@@ -4,6 +4,7 @@ on:
   workflow_dispatch:
   pull_request:
     paths:
+      - 'accelerator/**'
       - '.github/workflows/no-torch.yml'
       - 'op_builder/**'
   schedule:

accelerator/cpu_accelerator.py

@@ -3,9 +3,15 @@
 
 # DeepSpeed Team
 
-import torch
 from .abstract_accelerator import DeepSpeedAccelerator
 
+# During setup stage torch may not be installed, pass on no torch will
+# allow op builder related API to be executed.
+try:
+    import torch
+except ImportError as e:
+    pass
+
 try:
     import oneccl_bindings_for_pytorch  # noqa: F401 # type: ignore
     oneccl_imported_p = True