Remove redundant dependencies to prevent a dependency loop

Remove llvm dependency from mesa

packages/mesa.rb

@@ -33,7 +33,6 @@ class Mesa < Package
   depends_on 'python27'
   depends_on 'bison'
   depends_on 'libxshmfence'
-  depends_on 'llvm'
   depends_on 'elfutils'
   
   def self.build

packages/sommelier.rb

@@ -21,10 +21,7 @@ class Sommelier < Package
   })
 
   depends_on 'mesa'
-  depends_on 'pixman'
-  depends_on 'libxkbcommon'
   depends_on 'xwayland'
-  depends_on 'xkbcomp'
   depends_on 'psmisc'
   
   def self.build