LogDetail: update to use "&&" over "and"

Soy's and / or operators always return a Boolean. Recently, && and || operators have been introduced that match JavaScript semantics, which return either the first or second operand depending on truthiness.

Change-Id: Icadcfda890fe83de8f34525c5d7f997f36d4dd09

resources/com/google/gitiles/templates/LogDetail.soy

diff --git a/resources/com/google/gitiles/templates/LogDetail.soy b/resources/com/google/gitiles/templates/LogDetail.soy
index 108bbef..f231aa2 100644
--- a/resources/com/google/gitiles/templates/LogDetail.soy
+++ b/resources/com/google/gitiles/templates/LogDetail.soy
@@ -285,7 +285,7 @@
       rename or copy. */
 {call logEntry variant="'full'" data="all" /}
 
-{if $diffTree and length($diffTree)}
+{if $diffTree && length($diffTree)}
   <ul class="DiffTree">
     {for $entry in $diffTree}
       <li>