7069176: Update the JDK version numbers in Hotspot for JDK 8

Summary: Change JDK_MINOR_VER and JDK_PREVIOUS_VERSION to reflect JDK8 values
Reviewed-by: jcoomes

make/hotspot_version

@@ -38,8 +38,8 @@ HS_MINOR_VER=0
 HS_BUILD_NUMBER=01
 
 JDK_MAJOR_VER=1
-JDK_MINOR_VER=7
+JDK_MINOR_VER=8
 JDK_MICRO_VER=0
 
 # Previous (bootdir) JDK version
-JDK_PREVIOUS_VERSION=1.6.0
+JDK_PREVIOUS_VERSION=1.7.0