Fix memory leak when running tjunittest -yuv

Closes #61

ChangeLog.txt

@@ -19,6 +19,9 @@ to construct a JPEG image in which a single Huffman block is over 430 bytes
 long, so this version of libjpeg-turbo activates the accelerated Huffman
 decoder only if there are > 512 bytes of data in the input buffer.
 
+[3] Fixed a memory leak in tjunittest encountered when running the program
+with the -yuv option.
+
 
 1.4.2
 =====

tjunittest.c

@@ -638,7 +638,7 @@ void bufSizeTest(void)
 						&dstSize, subsamp, 100, alloc? 0:TJFLAG_NOREALLOC));
 				}
 				free(srcBuf);  srcBuf=NULL;
-				if(!alloc)
+				if(!alloc || doyuv)
 				{
 					tjFree(dstBuf);  dstBuf=NULL;
 				}
@@ -670,7 +670,7 @@ void bufSizeTest(void)
 						&dstSize, subsamp, 100, alloc? 0:TJFLAG_NOREALLOC));
 				}
 				free(srcBuf);  srcBuf=NULL;
-				if(!alloc)
+				if(!alloc || doyuv)
 				{
 					tjFree(dstBuf);  dstBuf=NULL;
 				}