Set empty img alt if not text is available

git-svn-id: https://svn.apache.org/repos/asf/maven/skins/trunk@1778134 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/maven-fluido-skin/src/main/resources/META-INF/maven/site-macros.vm b/maven-fluido-skin/src/main/resources/META-INF/maven/site-macros.vm
index 8361ca7..c253f86 100644
--- a/maven-fluido-skin/src/main/resources/META-INF/maven/site-macros.vm
+++ b/maven-fluido-skin/src/main/resources/META-INF/maven/site-macros.vm
@@ -165,7 +165,7 @@
 #*    *##elseif ( $banner.name )
 #*      *##set ( $alt = ' alt="' + $banner.name + '"' )
 #*    *##else
-#*      *##set ( $alt = "" )
+#*      *##set ( $alt = ' alt=""' )
 #*    *##end
 #*    *##if( $banner.border )
 #*      *##set ( $imgBorder = ' border="' + $banner.border + '"' )