[docs] updated HDFS guide (#1890)

* updated HDFS guide

* updated guide

* no info about Clang

* pass paths in quotes

* Update README.rst

docs/Installation-Guide.rst

@@ -580,12 +580,12 @@ Refer to `GPU Docker folder <https://github.com/Microsoft/LightGBM/tree/master/d
 Build HDFS Version
 ~~~~~~~~~~~~~~~~~~
 
-**Note**: Installation process of HDFS version is untested.
+HDFS version of LightGBM was tested on CDH-5.14.4 cluster.
 
 Linux
 ^^^^^
 
-On Linux HDFS version of LightGBM can be built using **CMake** and **gcc** or **Clang**.
+On Linux HDFS version of LightGBM can be built using **CMake** and **gcc**.
 
 1. Install `CMake`_.
 
@@ -596,6 +596,12 @@ On Linux HDFS version of LightGBM can be built using **CMake** and **gcc** or **
      git clone --recursive https://github.com/Microsoft/LightGBM ; cd LightGBM
      mkdir build ; cd build
      cmake -DUSE_HDFS=ON ..
+     # if you have installed HDFS to a customized location, you should specify paths to HDFS headers (hdfs.h) and library (libhdfs.so) like the following:
+     # cmake \
+     #   -DUSE_HDFS=ON \
+     #   -DHDFS_LIB="/opt/cloudera/parcels/CDH-5.14.4-1.cdh5.14.4.p0.3/lib64/libhdfs.so" \
+     #   -DHDFS_INCLUDE_DIR="/opt/cloudera/parcels/CDH-5.14.4-1.cdh5.14.4.p0.3/include/" \
+     #   ..
      make -j4
 
 Build Java Wrapper

python-package/README.rst

@@ -121,7 +121,7 @@ Build HDFS Version
 
     pip install lightgbm --install-option=--hdfs
 
-Note that the installation process of HDFS version is **untested**.
+Note that the installation process of HDFS version was tested only on **Linux**.
 
 Build with MinGW-w64 on Windows
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~