patch 8.1.0211: expanding a file name "~" results in $HOME

Problem:    Expanding a file name "~" results in $HOME. (Aidan Shafran)
Solution:   Change "~" to "./~" before expanding. (closes #3072)
diff --git a/src/if_cscope.c b/src/if_cscope.c
index 986663d..d621a14 100644
--- a/src/if_cscope.c
+++ b/src/if_cscope.c
@@ -519,7 +519,7 @@
 #ifdef FEAT_MODIFY_FNAME
     len = (int)STRLEN(fname);
     fbuf = (char_u *)fname;
-    (void)modify_fname((char_u *)":p", &usedlen,
+    (void)modify_fname((char_u *)":p", FALSE, &usedlen,
 					      (char_u **)&fname, &fbuf, &len);
     if (fname == NULL)
 	goto add_err;