crash-reporter: Remove libbase_ver override in gyp file.

CL:194476 modified platform2 to build against libchrome-242728. The
libbase_ver override in the gyp file is no longer needed.

BUG=chromium:361748
TEST=`FEATURES=test emerge-$BOARD platform2`
TEST=Verify that crash-reporter is linked against libchrome-242728.

Change-Id: I46a362165e08839bce82748f55f8f09595b8ac18
Reviewed-on: https://chromium-review.googlesource.com/196725
Commit-Queue: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>

crash-reporter.gyp

diff --git a/crash-reporter.gyp b/crash-reporter.gyp
index 0b9d9b1..daa1ed0 100644
--- a/crash-reporter.gyp
+++ b/crash-reporter.gyp
@@ -7,9 +7,6 @@
       ],
     },
   },
-  'variables': {
-    'libbase_ver': 242728,
-  },
   'targets': [
     {
       'target_name': 'libcrash',