git/branch: merge correct set of files

we were switching branches before we got the full list
of modified files, which could garble what we were trying
to merge.

sys/lib/git/common.rc

@@ -44,9 +44,9 @@ fn merge1 {@{
 	rfork e
 	n=$pid
 	out=$1
-	theirs=$2
+	ours=$2
 	base=$3
-	ours=$4
+	theirs=$4
 	tmp=$out.tmp
 	while(test -f $tmp){
 		tmp=$tmp.$n
@@ -70,8 +70,7 @@ fn merge1 {@{
 		rm -f $tmp $out
 		git/rm $out
 	}
-	}
-}
+}}
 
 fn gitup{
 	gitroot=`{git/conf -r >[2]/dev/null}