Convert existing die(..., strerror(errno)) to die_errno()

Change calls to die(..., strerror(errno)) to use the new die_errno().

In the process, also make slight style adjustments: at least state
_something_ about the function that failed (instead of just printing
the pathname), and put paths in single quotes.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin-rm.c b/builtin-rm.c
index 0cc4912..57975db 100644
--- a/builtin-rm.c
+++ b/builtin-rm.c
@@ -257,7 +257,7 @@
 				continue;
 			}
 			if (!removed)
-				die("git rm: %s: %s", path, strerror(errno));
+				die_errno("git rm: '%s'", path);
 		}
 	}