Fixed typo in copyright update script

build-scripts/update-copyright.sh

@@ -2,7 +2,7 @@
 
 find . -type f -exec grep -Il "Copyright" {} \;     \
 | grep -v \.hg                             \
-| while read $file;                            \
+| while read file;                            \
 do \
   LC_ALL=C sed -ie "s/\(.*Copyright.*\)[0-9]\{4\}\( *Sam Lantinga\)/\1`date +%Y`\2/" "$file"; \
   rm "${file}e"; \