CI: Fix missing close-paren )

circle.yml

diff --git a/circle.yml b/circle.yml
index 7ee2fa4..d9c2766 100644
--- a/circle.yml
+++ b/circle.yml
@@ -212,7 +212,7 @@
       for file in $(ls *.png); do
         # if evergreen browser, browser version of previous screenshot may not match,
         # so replace previous browser version with glob
-        baseline="$(echo baseline/$(echo $file | sed 's/[^_]*_(evergreen)/*/')"
+        baseline="$(echo baseline/$(echo $file | sed 's/[^_]*_(evergreen)/*/'))"
         echo "Number of different pixels from baseline in $file:"
         compare -metric AE $baseline $file ${file/%.png/_DIFF.png}
       done