packages: do not set default pkg branch to master

pkg/omf/functions/packages/omf.packages.install.fish

@@ -16,12 +16,10 @@ function omf.packages.install -a name_or_url
     set name $name_or_url
     set url $props[2]
     set branch $props[3]
-    if test -z "$branch"
-      set branch "master"
-    end
   else
     set name (omf.packages.name $name_or_url)
     set url $name_or_url
+    set branch ""
   end
 
   if contains -- $name (omf.packages.list)

pkg/omf/functions/repo/omf.repo.clone.fish

 function omf.repo.clone -a url branch path
-  command git clone --quiet $url -b $branch $path
+  if test -z "$branch"
+    command git clone --quiet $url $path
+  else
+    command git clone --quiet $url -b $branch $path
+  end
 end