Remove redundant lib*dll.def rules from .gitignore

Since we now have a global rule in the root .gitignore,
there's no need to keep directory-specific ones as well.

Noted by Peter Eisentraut

src/interfaces/ecpg/compatlib/.gitignore

 /compatlib.def
-/libecpg_compatdll.def
-/libecpg_compatddll.def
 /blibecpg_compatdll.def
 /exports.list

src/interfaces/ecpg/ecpglib/.gitignore

 /ecpglib.def
-/libecpgdll.def
-/libecpgddll.def
 /blibecpgdll.def
 /exports.list
 

src/interfaces/ecpg/pgtypeslib/.gitignore

 /pgtypeslib.def
-/libpgtypesdll.def
-/libpgtypesddll.def
 /blibpgtypesdll.def
 /exports.list
 

src/interfaces/libpq/.gitignore

@@ -18,5 +18,4 @@
 /ip.c
 /encnames.c
 /wchar.c
-/libpqdll.def
 /libpq.rc