remove noise pip-version-check noise that hides the outcome of the build (#998)

README.md

@@ -124,12 +124,12 @@ CUDA and C++ extensions via
 ```
 $ git clone https://github.com/NVIDIA/apex
 $ cd apex
-$ pip install -v --no-cache-dir --global-option="--cpp_ext" --global-option="--cuda_ext" ./
+$ pip install -v --disable-pip-version-check --no-cache-dir --global-option="--cpp_ext" --global-option="--cuda_ext" ./
 ```
 
 Apex also supports a Python-only build (required with Pytorch 0.4) via
 ```
-$ pip install -v --no-cache-dir ./
+$ pip install -v --disable-pip-version-check --no-cache-dir ./
 ```
 A Python-only build omits:
 - Fused kernels required to use `apex.optimizers.FusedAdam`.