[SPARK-11236][CORE] Update Tachyon dependency from 0.7.1 -> 0.8.0.

Upgrades the tachyon-client version to the latest release.

No new dependencies are added and no spark facing APIs are changed. The removal of the `tachyon-underfs-s3` exclusion will enable users to use S3 out of the box and there are no longer any additional external dependencies added by the module.

Author: Calvin Jia <jia.calvin@gmail.com>

Closes #9204 from calvinjia/spark-11236.

core/pom.xml

@@ -266,7 +266,7 @@
     <dependency>
       <groupId>org.tachyonproject</groupId>
       <artifactId>tachyon-client</artifactId>
-      <version>0.7.1</version>
+      <version>0.8.0</version>
       <exclusions>
         <exclusion>
           <groupId>org.apache.hadoop</groupId>
@@ -288,10 +288,6 @@
           <groupId>org.tachyonproject</groupId>
           <artifactId>tachyon-underfs-glusterfs</artifactId>
         </exclusion>
-        <exclusion>
-          <groupId>org.tachyonproject</groupId>
-          <artifactId>tachyon-underfs-s3</artifactId>
-        </exclusion>
       </exclusions>
     </dependency>
     <dependency>

make-distribution.sh

@@ -33,9 +33,9 @@ SPARK_HOME="$(cd "`dirname "$0"`"; pwd)"
 DISTDIR="$SPARK_HOME/dist"
 
 SPARK_TACHYON=false
-TACHYON_VERSION="0.7.1"
+TACHYON_VERSION="0.8.0"
 TACHYON_TGZ="tachyon-${TACHYON_VERSION}-bin.tar.gz"
-TACHYON_URL="https://github.com/amplab/tachyon/releases/download/v${TACHYON_VERSION}/${TACHYON_TGZ}"
+TACHYON_URL="http://tachyon-project.org/downloads/files/${TACHYON_VERSION}/${TACHYON_TGZ}"
 
 MAKE_TGZ=false
 NAME=none
@@ -240,10 +240,10 @@ if [ "$SPARK_TACHYON" == "true" ]; then
   fi
 
   tar xzf "${TACHYON_TGZ}"
-  cp "tachyon-${TACHYON_VERSION}/core/target/tachyon-${TACHYON_VERSION}-jar-with-dependencies.jar" "$DISTDIR/lib"
+  cp "tachyon-${TACHYON_VERSION}/assembly/target/tachyon-assemblies-${TACHYON_VERSION}-jar-with-dependencies.jar" "$DISTDIR/lib"
   mkdir -p "$DISTDIR/tachyon/src/main/java/tachyon/web"
   cp -r "tachyon-${TACHYON_VERSION}"/{bin,conf,libexec} "$DISTDIR/tachyon"
-  cp -r "tachyon-${TACHYON_VERSION}"/core/src/main/java/tachyon/web "$DISTDIR/tachyon/src/main/java/tachyon/web"
+  cp -r "tachyon-${TACHYON_VERSION}"/servers/src/main/java/tachyon/web "$DISTDIR/tachyon/src/main/java/tachyon/web"
 
   if [[ `uname -a` == Darwin* ]]; then
     # need to run sed differently on osx