GEODE-474: Upgrade Gradle version in wrapper to 2.8

Executed './gradlew clean test' for verification

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Wed Jan 07 11:19:52 PST 2015
+#Mon Oct 26 08:38:10 PDT 2015
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.3-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.8-bin.zip

gradlew

@@ -9,7 +9,7 @@
 # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
 DEFAULT_JVM_OPTS=""
 
-APP_NAME="GemFire"
+APP_NAME="Apache Geode (incubating)"
 APP_BASE_NAME=`basename "$0"`
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
@@ -42,11 +42,6 @@ case "`uname`" in
     ;;
 esac
 
-# For Cygwin, ensure paths are in UNIX format before anything is touched.
-if $cygwin ; then
-    [ -n "$JAVA_HOME" ] && JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
-fi
-
 # Attempt to set APP_HOME
 # Resolve links: $0 may be a link
 PRG="$0"
@@ -61,9 +56,9 @@ while [ -h "$PRG" ] ; do
     fi
 done
 SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >&-
+cd "`dirname \"$PRG\"`/" >/dev/null
 APP_HOME="`pwd -P`"
-cd "$SAVED" >&-
+cd "$SAVED" >/dev/null
 
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
@@ -114,6 +109,7 @@ fi
 if $cygwin ; then
     APP_HOME=`cygpath --path --mixed "$APP_HOME"`
     CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
 
     # We build the pattern for arguments to be converted via cygpath
     ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`