fs#4737 Avoid possibly racy use of mcam.url variable
fs#4737 Avoid possibly racy use of mcam.url variable

Some code calls fireCallbackRequest() using this anti-pattern:

  var previous = mcam.url;
  mcam.url = '/errands/hybrid/symphony';
  mcam.fireCallbackRequest(...);
  mcam.url = previous;

(One forgot to reset mcam.url to its previous value, which triggers
the bug reported in this tracker issue)

This can lead to race condition since the global variable mcam.url can
be modified by different code executing asynchronously, and the last one
that sets it "win".

Fix this by recognizing a "TARGET_URL" new_parameters element. The value
overrides the mcam.url value. This allows each caller to customize their
url without sharing a global variable.

cention/ferite-module-webframework,cention/ferite-module-webframework,cention/ferite-module-webframework