Revert 215101 "Linux: use sandbox binary alongside chrome."

It breaks the page cycler benchmarks.

BUG=267640

> Linux: use sandbox binary alongside chrome.
> 
> This removes linux_sandbox_path and instead expects sandbox binary
> to be in the same directory as chrome (or CHROME_DEVEL_SANDBOX to be
> set).
> 
> This will be helpful for SxS support on Linux, where the sandbox path
> would be different depending on channel.
> 
> BUG=38598
> R=avi@chromium.org, jln@chromium.org
> 
> Review URL: https://codereview.chromium.org/20197003

TBR=phajdan.jr@chromium.org

Review URL: https://codereview.chromium.org/21910004

git-svn-id: http://src.chromium.org/svn/trunk/src/build@215300 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

common.gypi

@@ -949,6 +949,11 @@
     # remaining.
     'win_third_party_warn_as_error%': 'true',
 
+    # This is the location of the sandbox binary. Chrome looks for this before
+    # running the zygote process. If found, and SUID, it will be used to
+    # sandbox the zygote process and, thus, all renderer processes.
+    'linux_sandbox_path%': '',
+
     # Clang stuff.
     'clang%': '<(clang)',
     'make_clang_dir%': 'third_party/llvm-build/Release+Asserts',