Implement ValveSoftware#1543 for HL2MP mods

Author: Bitl

game/mod_hl2mp/gameinfo.txt

@@ -42,7 +42,7 @@
 			// folder.
 			//
 			// Note that this folder is scanned only when the game is booted.
-			game+mod			|gameinfo_path|custom/*
+			game+mod+custom_mod	|gameinfo_path|custom/*
 
 			// Now search loose files.  We'll set the directory containing the gameinfo.txt file
 			// as the first "mod" search path (after any user customizations).  This is also the one

game/quiver/info_changelog.txt

@@ -93,6 +93,7 @@ Added the following Source SDK Pull Requests:
 	- #1539: Allow weapons with penetrating bullets to penetrate Medigun shield
 	- #1540: Fixed on-hit attributes not triggering on friendly disguises
 	- #1542: Add Convar to Remove print from having cheats on for Achievements
+	- #1543: Fix mounting of custom content in gameinfo
 
 Details:
 - Fixed a bug where the mini-crit damage effect doesn't show up when your shield breaks.

game/survivor2/gameinfo.txt

@@ -43,7 +43,7 @@
 			// folder.
 			//
 			// Note that this folder is scanned only when the game is booted.
-			game+mod			|gameinfo_path|custom/*
+			game+mod+custom_mod	|gameinfo_path|custom/*
 
 			// Now search loose files.  We'll set the directory containing the gameinfo.txt file
 			// as the first "mod" search path (after any user customizations).  This is also the one