HADOOP-17508. Simplify deps install instructions (#2664)

BUILDING.txt

@@ -76,21 +76,17 @@ Installing required packages for clean install of Ubuntu 14.04 LTS Desktop:
   $ make -j$(nproc)
   $ sudo make install
 * Protocol Buffers 3.7.1 (required to build native code)
-  $ mkdir -p /opt/protobuf-3.7-src \
-        && curl -L -s -S \
-          https://github.com/protocolbuffers/protobuf/releases/download/v3.7.1/protobuf-java-3.7.1.tar.gz \
-          -o /opt/protobuf-3.7.1.tar.gz \
-        && tar xzf /opt/protobuf-3.7.1.tar.gz --strip-components 1 -C /opt/protobuf-3.7-src \
-        && cd /opt/protobuf-3.7-src \
-        && ./configure\
-        && make install \
-        && rm -rf /opt/protobuf-3.7-src
+  $ curl -L -s -S https://github.com/protocolbuffers/protobuf/releases/download/v3.7.1/protobuf-java-3.7.1.tar.gz -o protobuf-3.7.1.tar.gz
+  $ mkdir protobuf-3.7-src
+  $ tar xzf protobuf-3.7.1.tar.gz --strip-components 1 -C protobuf-3.7-src && cd protobuf-3.7-src
+  $ ./configure
+  $ make -j$(nproc)
+  $ sudo make install
 * Boost
-  $ curl -L https://sourceforge.net/projects/boost/files/boost/1.72.0/boost_1_72_0.tar.bz2/download > boost_1_72_0.tar.bz2 \
-    && tar --bzip2 -xf boost_1_72_0.tar.bz2 \
-    && cd boost_1_72_0 \
-    && ./bootstrap.sh --prefix=/usr/ \
-    && ./b2 --without-python install
+  $ curl -L https://sourceforge.net/projects/boost/files/boost/1.72.0/boost_1_72_0.tar.bz2/download > boost_1_72_0.tar.bz2
+  $ tar --bzip2 -xf boost_1_72_0.tar.bz2 && cd boost_1_72_0
+  $ ./bootstrap.sh --prefix=/usr/
+  $ ./b2 --without-python install
 
 Optional packages: