Fix a class of spurious clib_memcpy (...) warnings, VPP-486

Coverity doesn't understand the vector-unit memcpy functions. #ifdef
them out of the way when running a coverity scan.

Change-Id: I312eec1c861c1d3722510d2c121fb5f398fca868
Signed-off-by: Dave Barach <dave@barachs.net>

vppinfra/vppinfra/string.h

@@ -56,6 +56,11 @@
 /* Exchanges source and destination. */
 void clib_memswap (void *_a, void *_b, uword bytes);
 
+/*
+ * the vector unit memcpy variants confuse coverity
+ * so don't let it anywhere near them.
+ */
+#ifndef __COVERITY__
 #if __AVX__
 #include <vppinfra/memcpy_avx.h>
 #elif __SSSE3__
@@ -63,6 +68,9 @@ void clib_memswap (void *_a, void *_b, uword bytes);
 #else
 #define clib_memcpy(a,b,c) memcpy(a,b,c)
 #endif
+#else /* __COVERITY__ */
+#define clib_memcpy(a,b,c) memcpy(a,b,c)
+#endif
 
 #endif /* included_clib_string_h */