Unconditionally allow p{read,write}{,v}().
Unconditionally allow p{read,write}{,v}().

TEST=make test, also run browser_tests in Chrome
BUG=http://code.google.com/p/chromium/issues/detail?id=89114
Review URL: http://codereview.chromium.org/7387002
dj091111/seccompsandbox,marylinh/seccompsandbox,aman-iitj/seccompsandbox,aman-iitj/seccompsandbox,marylinh/seccompsandbox,dj091111/seccompsandbox,aman-iitj/seccompsandbox,marylinh/seccompsandbox,dj091111/seccompsandbox