rm extra checks in gimmes

gimmes/my/difftool

@@ -1,2 +1,2 @@
 #!/bin/bash
-has colordiff  ||  gimme colordiff
+gimme colordiff

gimmes/my/mergetool

@@ -2,5 +2,5 @@
 if [[ "$OS" = "Darwin" ]]; then
 	[[ -d "$HOME/Applications/SourceTree.app" ]]  ||  brew cask install sourcetree
 else
-	has meld  ||  gimme meld
+	gimme meld
 fi