Fix a typo 'iff' => 'if'

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@164766 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/StaticAnalyzer/Checkers/MacOSKeychainAPIChecker.cpp b/lib/StaticAnalyzer/Checkers/MacOSKeychainAPIChecker.cpp
index 21db9e6..b4a2210 100644
--- a/lib/StaticAnalyzer/Checkers/MacOSKeychainAPIChecker.cpp
+++ b/lib/StaticAnalyzer/Checkers/MacOSKeychainAPIChecker.cpp
@@ -240,8 +240,8 @@
 // 1) noErr / [0]
 // 2) someErr / [1, inf]
 // 3) unknown
-// If noError, returns true iff (1).
-// If !noError, returns true iff (2).
+// If noError, returns true if (1).
+// If !noError, returns true if (2).
 bool MacOSKeychainAPIChecker::definitelyReturnedError(SymbolRef RetSym,
                                                       ProgramStateRef State,
                                                       SValBuilder &Builder,