Fix linter warnings in faiss-gpu Conda build script (#3463)

Summary:

Satisfying linter warnings from a previous change

Reviewed By: junjieqi

Differential Revision: D57581364

conda/faiss-gpu/build-lib.sh

@@ -7,10 +7,10 @@
 set -e
 
 # Workaround for CUDA 11.4.4 builds. Moves all necessary headers to include root.
-if [[ -n "$FAISS_FLATTEN_CONDA_INCLUDES" && "$FAISS_FLATTEN_CONDA_INCLUDES" == "1" ]]; then
-  cp -r -n $CONDA_PREFIX/x86_64-conda-linux-gnu/sysroot/usr/include/* $CONDA_PREFIX/include/
-  cp -r -n $CONDA_PREFIX/x86_64-conda-linux-gnu/include/c++/11.2.0/* $CONDA_PREFIX/include/
-  cp -r -n $CONDA_PREFIX/x86_64-conda-linux-gnu/include/c++/11.2.0/x86_64-conda-linux-gnu/* $CONDA_PREFIX/include/
+if [ -n "$FAISS_FLATTEN_CONDA_INCLUDES" ] && [ "$FAISS_FLATTEN_CONDA_INCLUDES" = "1" ]; then
+  cp -r -n "$CONDA_PREFIX/x86_64-conda-linux-gnu/sysroot/usr/include/"* "$CONDA_PREFIX/include/"
+  cp -r -n "$CONDA_PREFIX/x86_64-conda-linux-gnu/include/c++/11.2.0/"* "$CONDA_PREFIX/include/"
+  cp -r -n "$CONDA_PREFIX/x86_64-conda-linux-gnu/include/c++/11.2.0/x86_64-conda-linux-gnu/"* "$CONDA_PREFIX/include/"
 fi
 
 # Build libfaiss.so/libfaiss_avx2.so/libfaiss_avx512.so