fix version check in Cygwin

Author: liufengyun

dist/bin/common

@@ -64,7 +64,7 @@ fi
 # parses 1.7, 1.8, 9, etc out of java version "1.8.0_91"
 JAVA_VERSION=$("$JAVACMD" -version 2>&1 | grep ' version "' | sed 's/.*version "\([0-9]*\)\(\.[0-9]*\)\{0,1\}\(.*\)*"/\1\2/; 1q')
 
-if [ "$JAVA_VERSION" != "1.8" ] ; then
+if [[ "$JAVA_VERSION" != "1.8"* ]] ; then                  # * for cygwin : trailing space
   echo "Error: Java 8 is required, actual $JAVA_VERSION"
   exit 1
 fi