Revert of do not hardcode -I/usr/include32 when cross-compiling (patchset #1...

Revert of do not hardcode -I/usr/include32 when cross-compiling (patchset #1 id:1 of https://codereview.chromium.org/1132853010/)

Reason for revert:
Looks like this broke some builds, where 'use_sysroot' isn't defined. See http://crbug.com/489783.

Sounds like sbc has an alternative solution here: https://codereview.chromium.org/1142793003/

Original issue's description:
> do not hardcode -I/usr/include32 when cross-compiling
>
> When we cross-compile, we do not want any /usr/include paths as that will
> conflict with our own system headers.  Disable the hardcoded path when we
> have an active sysroot.
>
> BUG=chromium:488360
>
> Committed: https://crrev.com/58b42a0c48127c60baad7ea79ea0e5576c6e1d0b
> Cr-Commit-Position: refs/heads/master@{#330514}

TBR=jochen@chromium.org,cjhopman@chromium.org,dpranke@chromium.org,phajdan.jr@chromium.org,scottmg@chromium.org,thakis@chromium.org,vapier@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=488360,489783

Review URL: https://codereview.chromium.org/1147793003

Cr-Commit-Position: refs/heads/master@{#330656}

build/common.gypi

@@ -3869,7 +3869,7 @@
                   # and make sure a 32-bit-on-64-bit build picks up the
                   # right files.
                   # For android build, use NDK headers instead of host headers
-                  ['host_arch!="ia32" and OS!="android" and use_sysroot!=1', {
+                  ['host_arch!="ia32" and OS!="android"', {
                     'include_dirs+': [
                       '/usr/include32',
                     ],