Minor fixes in the testsuite.

* tests/extrac07.at: Fix a typo (invalid number
of arguments before format list).
* tests/link02.at: Use `ln' instead of `link'.
* tests/link03.at: Likewise.

tests/extrac07.at

@@ -52,7 +52,7 @@ Extract
 dir/
 dir/foo
 ],
-[],[],[ustar]) # Testing one format is enough
+[],[],[],[ustar]) # Testing one format is enough
 
 AT_CLEANUP
 

tests/link02.at

@@ -34,9 +34,9 @@ AT_KEYWORDS([hardlinks link02])
 
 AT_TAR_CHECK([
 genfile -l 64 -f file1
-link file1 file2
-link file2 file3
-link file3 file4
+ln file1 file2
+ln file2 file3
+ln file3 file4
 tar -c -f archive --remove-files file1 file2 file3 file4
 tar tfv archive | sed -n 's/.*file[[2-4]] link to //p'
 ],

tests/link03.at

@@ -26,9 +26,9 @@ AT_KEYWORDS([hardlinks link03])
 
 m4_define([create_files],[
 genfile -l 64 -f file1
-link file1 file2
-link file2 file3
-link file3 file4
+ln file1 file2
+ln file2 file3
+ln file3 file4
 ])
 
 AT_TAR_CHECK([