Update Spanish scripts translation

Closes: #685297

[guillem@debian.org:
 - Remove trailing dots.
 - Align some option descriptions.
 - Uncapitalize words to match original text. ]

Signed-off-by: Guillem Jover <guillem@debian.org>

debian/changelog

@@ -13,6 +13,7 @@ dpkg (1.16.9) UNRELEASED; urgency=low
 
   [ Updated scripts translations ]
   * Polish (Michał Kułach). Closes: #683104
+  * Spanish (Omar Campagne). Closes: #685297
 
   [ Updated dselect translations ]
   * Czech (Miroslav Kure).