Update spack.yaml to test without arch in the specs

spack.yaml

@@ -19,6 +19,6 @@ spack:
     - py-pynn %gcc@10.3.0 
     - tvb-data %gcc@10.3.0
     - tvb-library ^binutils+ld+gold %gcc@10.3.0
-    - tvb-storage ^binutils+ld+gold %gcc@10.3.0 arch=linux-centos7-broadwell
-    - tvb-framework ^binutils+ld+gold %gcc@10.3.0 arch=linux-centos7-broadwell
+    - tvb-storage ^binutils+ld+gold %gcc@10.3.0
+    - tvb-framework ^binutils+ld+gold %gcc@10.3.0
     - meta-brainscales %gcc@10.3.0