@brief Remove a graph

`graph_module._drop(graphName, dropCollections)`

A graph can be dropped by its name.
This will automatically drop all collections contained in the graph as
long as they are not used within other graphs.
To drop the collections, the optional parameter *drop-collections* can be set to *true*.

@PARAMS

@PARAM{graphName, string, required}
Unique identifier of the graph

@PARAM{dropCollections, boolean, optional}
Define if collections should be dropped (default: false)

@EXAMPLES

Drop a graph and keep collections:

@EXAMPLE_ARANGOSH_OUTPUT{generalGraphDropGraphKeep}
~ var examples = require("@arangodb/graph-examples/example-graph.js");
~ var g1 = examples.loadGraph("social");
  var graph_module = require("@arangodb/general-graph");
  graph_module._drop("social");
  db._collection("female");
  db._collection("male");
  db._collection("relation");
~ db._drop("female");
~ db._drop("male");
~ db._drop("relation");
~ examples.dropGraph("social");
@END_EXAMPLE_ARANGOSH_OUTPUT

@EXAMPLE_ARANGOSH_OUTPUT{generalGraphDropGraphDropCollections}
~ var examples = require("@arangodb/graph-examples/example-graph.js");
~ var g1 = examples.loadGraph("social");
  var graph_module = require("@arangodb/general-graph");
  graph_module._drop("social", true);
  db._collection("female");
  db._collection("male");
  db._collection("relation");
@END_EXAMPLE_ARANGOSH_OUTPUT