Revert r292047: Replace compiling flag "-O3" with "-O2" to avoid a compiler bug that caused a crash

TBR=sergeyu@chromium.org
BUG=414919

Review URL: https://codereview.chromium.org/588703002

git-svn-id: http://src.chromium.org/svn/trunk/deps/third_party/libsrtp@292049 4ff67af0-8c30-449e-8e8b-ad334ec8d88c
diff --git a/libsrtp.gyp b/libsrtp.gyp
index 2fb0bcd..fd6f204 100644
--- a/libsrtp.gyp
+++ b/libsrtp.gyp
@@ -55,15 +55,6 @@
           # test applications and libjingle.
           'CPU_CISC',
         ],
-        # TODO(jiayl): There seems to be a bug in the compiler that causes a
-        # crash (crbug/414919) using -O3. Remove this change once the compiler
-        # is fixed.
-        'cflags!': [
-          '-O3',
-        ],
-        'cflags': [
-          '-O2',
-        ],
       }],
       ['target_arch=="mipsel" or target_arch=="mips64el"', {
         'defines': [