hgtags: delete "release" (prepare for new release)

R=r
CC=golang-dev
https://golang.org/cl/183123
diff --git a/.hgtags b/.hgtags
index 7f12632..185291f 100644
--- a/.hgtags
+++ b/.hgtags
@@ -6,4 +6,3 @@
 e205103b02e7393d4719df5faac2dac808234d3f release.2009-12-07
 3a47d2e3882bb12129de05382a2c131bb0c00964 release.2009-12-09
 a6fcf4303b0a92cce4011556b1c96044252d93af release.2009-12-22
-a6fcf4303b0a92cce4011556b1c96044252d93af release