Fix typo in r8_release.py

Change-Id: I469a1f4445b073a1334529fa44983327095f75f9
diff --git a/tools/utils.py b/tools/utils.py
index 3200b3a..2a4b18e 100644
--- a/tools/utils.py
+++ b/tools/utils.py
@@ -636,7 +636,7 @@
     # Build metadata currently not suppported
 
   def larger_than(self, other):
-    if self.prepelease or other.prepelease:
+    if self.prerelease or other.prerelease:
       raise Exception("Comparison with prerelease not implemented")
     if self.major > other.major:
       return True