libmodprobe: add support to remove modules

Add a remove method which will unload a given module from the kernel,
along with any modules it depended on, assuming those modules are now
unused.

Change-Id: Ie66dc153ef1771f50e26421d38d3656e95954780
diff --git a/libmodprobe/libmodprobe_ext_test.cpp b/libmodprobe/libmodprobe_ext_test.cpp
index 0f073cb..ca1c081 100644
--- a/libmodprobe/libmodprobe_ext_test.cpp
+++ b/libmodprobe/libmodprobe_ext_test.cpp
@@ -51,6 +51,16 @@
     return true;
 }
 
+bool Modprobe::Rmmod(const std::string& module_name) {
+    for (auto it = modules_loaded.begin(); it != modules_loaded.end(); it++) {
+        if (*it == module_name) {
+            modules_loaded.erase(it);
+            return true;
+        }
+    }
+    return false;
+}
+
 bool Modprobe::ModuleExists(const std::string& module_name) {
     auto deps = GetDependencies(module_name);
     if (deps.empty()) {