[Release] releases.py should not crash on non-release versions

tools/release/releases.py

Index: tools/release/releases.py
diff --git a/tools/release/releases.py b/tools/release/releases.py
index 5b826fccba089d27afc2f0cab0fefc209ae033af..7b659ccb80693fd4dc4a5009239547b89c49d21a 100755
--- a/tools/release/releases.py
+++ b/tools/release/releases.py
@@ -463,10 +463,15 @@ class RetrieveInformationOnChromeReleases(Step):
   def _GetGitHashForV8Version(self, v8_version):
     if v8_version == "N/A":
       return ""
+
+    real_v8_version = v8_version
     if v8_version.split(".")[3]== "0":
-      return self.GitGetHashOfTag(v8_version[:-2])
+      real_v8_version = v8_version[:-2]
 
-    return self.GitGetHashOfTag(v8_version)
+    try:
+      return self.GitGetHashOfTag(real_v8_version)
+    except GitFailedException:
+      return ""
 
   def _CreateCandidate(self, current_version):
     params = None