package/solarus: update license.txt file hash and remove license_gpl.txt hash.

The license.txt file has been updated with Solarus Free Resource Pack URL.

Before version 1.6.0, the archive was downloaded from github and license_gpl.txt
file which is present in the git repository.
Since version 1.6.0, the archive is downloaded from [1] but the license_gpl.txt
file is missing.

This has been reported upstream [2].

[1] http://www.solarus-games.org
[2] https://gitlab.com/solarus-games/solarus/issues/1328

Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/solarus/solarus.hash

@@ -1,5 +1,4 @@
 # Locally calculated
 sha256 d800fdf388f860732f2d40c8dd635c34fd1c452857f75bf9b3a421e3ef5ee751  solarus-1.6.0-src.tar.gz
 
-sha256 09cb24006b6a3f2698d8851dc5df4f413c1a98e20d4008bffd76ec236f14244d  license.txt
-sha256 8ceb4b9ee5adedde47b31e975c1d90c73ad27b6b165a1dcd80c7c545eb65b903  license_gpl.txt
+sha256 309875d925041d909bc705473d6c4b7905272aea15c1c2389088c26c161bae1f  license.txt

package/solarus/solarus.mk

@@ -10,7 +10,7 @@ SOLARUS_SOURCE = solarus-$(SOLARUS_VERSION)-src.tar.gz
 
 SOLARUS_LICENSE = GPL-3.0 (code), CC-BY-SA-4.0 (Solarus logos and icons), \
 	CC-BY-SA-3.0 (GUI icons)
-SOLARUS_LICENSE_FILES = license.txt license_gpl.txt
+SOLARUS_LICENSE_FILES = license.txt
 
 # Install libsolarus.so
 SOLARUS_INSTALL_STAGING = YES