pgit.sh: Fix some situation in which git errors were ignored and iterated on

Signed-off-by: Jan Lindemann <jan@janware.com>

scripts/pgit.sh

@@ -43,7 +43,7 @@ run()
 
 	for d in $pdirs; do
 		marker $d
-		(cd $d; git $cmd "$@")
+		git -C $d $cmd "$@"
 	done
 )}
 
@@ -66,11 +66,8 @@ clone()
 		}
 		marker "cloning $p"
 		git clone ssh://$id@git.jannet.de/srv/git/$id/proj/$p
-		(
+		git -C $p submodule init || fatal git submodule init failed in `pwd`
-			cd $p
+		git -C $p submodule update || fatal git submodule update failed in `pwd`
-			git submodule init
-			git submodule update
-		)
 	done
 )}
 
@@ -81,7 +78,7 @@ diff()
 	cd $pdir
 	for d in $pdirs; do
 		marker $d
-		(cd $d; git diff --src-prefix=a/$d/ --dst-prefix=b/$d/ "$@")
+		git -C $d diff --src-prefix=a/$d/ --dst-prefix=b/$d/ "$@"
 	done
 )}