Update release_beta to avoid problems

tools/release_beta.sh

@@ -42,6 +42,7 @@ function Build {
   DESCRIPTION=$4
   SPARKLE_PREFIX=$5
   codesign --verify --verbose "build/$BUILDTYPE/iTerm2.app" || die "Signature not verified"
+  (codesign -dv --verbose=4 build/$BUILDTYPE/iTerm.app 2>&1) | fgrep 'Authority=Developer ID Application: GEORGE NACHMAN (H7V7XYVQ7D)' || die "Not signed with the right certificate"
   pushd "build/$BUILDTYPE"
  
   # Create the zip file