Fix Java build

Summary:
The PATH update should put the Java path in the beginning, rather than the end. Otherwise, it will be overwritten. Also upgrade the Java version.
Closes https://github.com/facebook/rocksdb/pull/1912

Differential Revision: D4609854

Pulled By: siying

fbshipit-source-id: 3dc04f2

build_tools/rocksdb-lego-determinator

@@ -89,7 +89,7 @@ TSAN="COMPILE_WITH_TSAN=1"
 UBSAN="COMPILE_WITH_UBSAN=1"
 DISABLE_JEMALLOC="DISABLE_JEMALLOC=1"
 HTTP_PROXY="https_proxy=http://fwdproxy.29.prn1:8080 http_proxy=http://fwdproxy.29.prn1:8080 ftp_proxy=http://fwdproxy.29.prn1:8080"
-SETUP_JAVA_ENV="export $HTTP_PROXY; export JAVA_HOME=/usr/local/jdk-7u10-64/; export PATH=\$PATH:\$JAVA_HOME/bin"
+SETUP_JAVA_ENV="export $HTTP_PROXY; export JAVA_HOME=/usr/local/jdk-8u60-64/; export PATH=\$JAVA_HOME/bin:\$PATH"
 PARSER="'parser':'python build_tools/error_filter.py $1'"
 
 CONTRUN_NAME="ROCKSDB_CONTRUN_NAME"