support/download/git: Fix compatibility issue with git older than 1.8.4

The "--no-patch" option used by the git downloader appeared on git
1.8.4. Systems with older git versions show an error and fall back to
the wget downloader, which isn't suitable for all the cases.

Signed-off-by: Enrique Ocaña González <eocanha@igalia.com>
Tested-by: Matthew Weber <matthew.weber@rockwellcollins.com>
Tested-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Acked-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

support/download/git

@@ -76,7 +76,7 @@ _git checkout -q "'${cset}'"
 
 # Get date of commit to generate a reproducible archive.
 # %cD is RFC2822, so it's fully qualified, with TZ and all.
-date="$( _git show --no-patch --pretty=format:%cD )"
+date="$( _git log -1 --pretty=format:%cD )"
 
 # There might be submodules, so fetch them.
 if [ ${recurse} -eq 1 ]; then