bitbake: bitbake/hob: removing extra parameters from conf files using hob

In Hob settings, there is a tab to add/remove extra settings. This
patch implements a way to "remove" variables from conf files, through
bitbake. But, to keep the history assigment of the variables synchronized,
instead of removing, it replaces the lines with blank lines.

[YOCTO #5284]
(Bitbake rev: bd720fb63cef6b399619b8fbcaeb8d7710f2d6df)

Signed-off-by: Cristiana Voicu <cristiana.voicu@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/command.py

@@ -241,6 +241,13 @@ class CommandsSync:
         op = params[3]
         command.cooker.modifyConfigurationVar(var, val, default_file, op)
 
+    def removeVarFile(self, command, params):
+        """
+        Remove a variable declaration from a file
+        """
+        var = params[0]
+        command.cooker.removeConfigurationVar(var)
+
     def createConfigFile(self, command, params):
         """
         Create an extra configuration file