[NIXL] Bump NIXL version to 1.5.1 (#63817)

Signed-off-by: Jie Hao <jihao@nvidia.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
Co-authored-by: vllm-agent <claw@inferact.ai>

requirements/kv_connectors.txt

@@ -2,7 +2,7 @@ lmcache >= 0.5.6
 # CuPy 14.1.0 imports pytest from cupy.testing._random, which breaks runtime
 # images. 14.1.1 fixes the root cause, so only 14.1.0 is excluded.
 cupy-cuda13x != 14.1.0
-nixl == 1.5.0
+nixl == 1.5.1
 # CUDA 12 build. On the CUDA 13 image install-kv-connectors.sh swaps this for
 # the mooncake-transfer-engine-cuda13 variant of the same version.
 mooncake-transfer-engine >= 0.3.12

requirements/kv_connectors_cu12.txt

@@ -3,5 +3,5 @@
 lmcache == 0.5.6
 cuda-python >= 12, < 13
 cupy-cuda12x != 14.1.0
-nixl == 1.5.0
+nixl == 1.5.1
 mooncake-transfer-engine >= 0.3.12